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I am trying to find a simple way to perform a set of javascript math operations without using eval() function. Example: 1+2x3x400+32/2+3 and it must follow the PEMDAS math principle. This is what I have, but it doesn't work exactly it should.
function mdas(equation) {
let operations = ["*", "/", "+", "-"];
for (let outerCount = 0; outerCount < operations.length; outerCount++) {
for (let innerCount = 0; innerCount < equation.length; ) {
if (equation[innerCount] == operations[outerCount]) {
let operationResult = runOperation(equation[innerCount - 1], operations[outerCount], equation[innerCount + 1]);
var leftSideOfEquation = equation.substr(0, equation.indexOf(innerCount - 1));
var rightSideOfEquation = equation.substr(equation.indexOf(innerCount), equation.length);
var rightSideOfEquation = rightSideOfEquation.replace(rightSideOfEquation[0],String(operationResult));
equation = leftSideOfEquation + rightSideOfEquation;
innerCount = 0;
}
else {
innerCount++;
}
}
}
return "Here is it: " + equation; //result of the equation
}
If you don't want to use a complete library like mathjs - and you don't want to tackle creating your own script which would involve: lexical analysis, tokenization, syntax analysis, recursive tree parsing, compiling and output...
the simplest banal suggestion: Function
const calc = s => Function(`return(${s})`)();
console.log( calc("1+2*3*400+32/2+3") ); // 2420
console.log( calc("-3*-2") ); // 6
console.log( calc("-3 * + 1") ); // -3
console.log( calc("-3 + -1") ); // -4
console.log( calc("2 * (3 + 1)") ); // 8
My take at a custom MDAS
Here I created a Regex to retrieve operands and operators, accounting for negative values: /(-?[\d.]+)([*\/+-])?/g.
Firstly we need to remove any whitespace from our string using str.replace(/ /g , "")
Using JavaScript's String.prototype.matchAll() we can get a 2D array with all the matches as [[fullMatch, operand, operator], [.. ] we can than further flatten it using Array.prototype.flat()
Having that flattened array, we can now filter it using Array.prototype.filter() to remove the fullMatch -es returned by the regular expression and remove the last undefined value.
Define a calc Object with the needed operation functions
Iterate over the MDAS groups */ and than +- as regular expressions /\/*/ and /+-/
Consume finally the array of matches until only one array key is left
let str = "-1+2 * 3*+400+-32 /2+3.1"; // 2386.1
str = str.replace(/ +/g, ""); // Remove all spaces!
// Get operands and operators as array.
// Remove full matches and undefined values.
const m = [...str.matchAll(/(-?[\d.]+)([*\/+-])?/g)].flat().filter((x, i) => x && i % 3);
const calc = {
"*": (a, b) => a * b,
"/": (a, b) => a / b,
"+": (a, b) => a + b,
"-": (a, b) => a - b,
};
// Iterate by MDAS groups order (first */ and than +-)
[/[*\/]/, /[+-]/].forEach(expr => {
for (let i = 0; i < m.length; i += 2) {
let [a, x, b] = [m[i], m[i + 1], m[i + 2]];
x = expr.exec(x);
if (!x) continue;
m[i] = calc[x.input](parseFloat(a), parseFloat(b)); // calculate and insert
m.splice(i + 1, 2); // remove operator and operand
i -= 2; // rewind loop
}
});
// Get the last standing result
console.log(m[0]); // 2386.1
It's a little hacky, but you can try something like this:
var eqs = [
'1+2*3*4+1+1+3',
'1+2*3*400+32/2+3',
'-5+2',
'3*-2',
];
for(var eq in eqs) { console.log(mdas(eqs[eq])); }
function mdas(equation) {
console.log(equation);
var failsafe = 100;
var num = '(((?<=[*+-])-|^-)?[0-9.]+)';
var reg = new RegExp(num + '([*/])' + num);
while(m = reg.exec(equation)) {
var n = (m[3] == "*") ? m[1]*m[4] : m[1]/m[4];
equation = equation.replace(m[0], n);
if(failsafe--<0) { return 'failsafe'; }
}
var reg = new RegExp(num + '([+-])' + num);
while(m = reg.exec(equation)) {
var n = (m[3] == "+") ? 1*m[1] + 1*m[4] : m[1]-m[4];
equation = equation.replace(m[0], n);
if(failsafe--<0) { return 'failsafe'; }
}
return equation;
}
Given a non-negative number say 1213, it should return 12 because there are 12 possible integers similar to 1213 i.e., 1123,1132,1213,1231,1312,1321,2113,2131,2311,312,3121 and 3211. Same with 10, it should return 1 and 12 should return 2 and if the number is 120 it should return 4 as combinations are 120,102,210,201.
You can use this formula to get the total number of unique permutations excluding permutations with leading zero.
Lets define some symbols:
n = Total Number of digits
z = Number of zeros
r1, r2, ..., rn = repetition count of digits with count > 1
fact(p) = factorial of number of p
Total permutations = (n - z) * fact(n - 1) / fact(r1) * fact(r2) * .... * fact(rn)
For example, for 1213,
n = 4, z = 0, r1 (digit 1) = 2
permutations = (4 - 0) * fact(4 - 1) / fact(2) = 4 * 6 / 2 = 12
You can easily convert this to program.
function factorial(n) {
if (n <=1)
return 1;
return n * factorial(n-1);
}
function getPermutations(number) {
var n = number.toString().split('').length;
var r = {};
number.toString().split('').forEach(function(digit){
r[digit] = r[digit] || 0;
r[digit] += 1;
});
var z = number.toString().split('').reduce(function(count, digit) {
return (digit === '0') ? count + 1 : count;
}, 0);
var denominator = Object.keys(r).map(function (key) { return r[key]; }).reduce(function(result, curr) {
return result * factorial(curr);
}, 1);
//console.log(n, r, z);
return (n - z) * factorial(n - 1) / denominator;
}
var result = getPermutations(1216);
console.log(result);
Note : This is basic implementation and would not be the most optimum. Also, factorial calculation involves large numbers and would probably fail for large inputs.
You are looking for an anagram algorithm :
This script find every anagram of a string then delete every number starting with zero :
var allAnagrams = function(arr) {
var anagrams = {};
arr.forEach(function(str) {
var recurse = function(ana, str) {
if (str === '')
anagrams[ana] = 1;
for (var i = 0; i < str.length; i++)
recurse(ana + str[i], str.slice(0, i) + str.slice(i + 1));
};
recurse('', str);
});
return Object.keys(anagrams);
}
var arr = ['120']; //declare your number
var anag = allAnagrams(arr); //send it to the function
for (var i in anag) { //delete leading 0
if((anag[i].charAt(0)) === '0' ) {
anag.splice(i);
}
}
console.log(anag); //print array
console.log(anag.length); // print length
Here the output will be :
["102", "120", "201", "210"]
4
I would like to convert numbers between different bases, such as hexadecimal and decimal.
Example: How do you convert hexadecimal 8F to decimal?
The API
To convert to a number from a hex string:
parseInt(string, radix)
string: Required. The string to be parsed
radix: Optional. A number (from 2 to 36) that represents the numeral system to be used
To convert from a number to a hex string:
NumberObject.toString(radix)
radix: Optional. Specifies the base radix you would like the number displayed as.
Example radix values:
2 - The number will show as a binary value
8 - The number will show as an octal value
16 - The number will show as an hexadecimal value
Example Usage
Integer value to hex:
var i = 10;
console.log( i.toString(16) );
Hex string to integer value:
var h = "a";
console.log( parseInt(h, 16) );
Integer value to decimal:
var d = 16;
console.log( d.toString(10) );
Update 2023-01-05: Now supports large numbers and floats via https://github.com/ryansmith94/baseroo
I came to this post needing to convert from base 10 to 62 and vice-versa. Whilst the solutions here are great, parseInt and toString only support base 2 to 36. So if anyone finds themselves in a similar position to me needing base 2 to 62, I've pasted my solution below.
function convertBase(value, from_base, to_base) {
var range = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/'.split('');
var from_range = range.slice(0, from_base);
var to_range = range.slice(0, to_base);
var dec_value = value.split('').reverse().reduce(function (carry, digit, index) {
if (from_range.indexOf(digit) === -1) throw new Error('Invalid digit `'+digit+'` for base '+from_base+'.');
return carry += from_range.indexOf(digit) * (Math.pow(from_base, index));
}, 0);
var new_value = '';
while (dec_value > 0) {
new_value = to_range[dec_value % to_base] + new_value;
dec_value = (dec_value - (dec_value % to_base)) / to_base;
}
return new_value || '0';
}
You may try the following code, which also supports arbitrary precision numbers (larger than 2^53).
function convertBase(str, fromBase, toBase) {
const DIGITS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/";
const add = (x, y, base) => {
let z = [];
const n = Math.max(x.length, y.length);
let carry = 0;
let i = 0;
while (i < n || carry) {
const xi = i < x.length ? x[i] : 0;
const yi = i < y.length ? y[i] : 0;
const zi = carry + xi + yi;
z.push(zi % base);
carry = Math.floor(zi / base);
i++;
}
return z;
}
const multiplyByNumber = (num, x, base) => {
if (num < 0) return null;
if (num == 0) return [];
let result = [];
let power = x;
while (true) {
num & 1 && (result = add(result, power, base));
num = num >> 1;
if (num === 0) break;
power = add(power, power, base);
}
return result;
}
const parseToDigitsArray = (str, base) => {
const digits = str.split('');
let arr = [];
for (let i = digits.length - 1; i >= 0; i--) {
const n = DIGITS.indexOf(digits[i])
if (n == -1) return null;
arr.push(n);
}
return arr;
}
const digits = parseToDigitsArray(str, fromBase);
if (digits === null) return null;
let outArray = [];
let power = [1];
for (let i = 0; i < digits.length; i++) {
digits[i] && (outArray = add(outArray, multiplyByNumber(digits[i], power, toBase), toBase));
power = multiplyByNumber(fromBase, power, toBase);
}
let out = '';
for (let i = outArray.length - 1; i >= 0; i--)
out += DIGITS[outArray[i]];
return out;
}
Usage:
console.log(convertBase("5a2a9c826c75045be9ba8fbffc80c6f25a2a9c826c75045be9ba8fbffc80c6f2",16,64));
// Returns: 5EGD89ItghrWrGfL/O0NL9qaFO2r7k4m+CWzX/YwcrO
console.log(convertBase("5EGD89ItghrWrGfL/O0NL9qaFO2r7k4m+CWzX/YwcrO",64,16));
// Returns: 5a2a9c826c75045be9ba8fbffc80c6f25a2a9c826c75045be9ba8fbffc80c6f2
The basic code has been found here, I have a bit improved it to also support up to base 64.
The following diagram might help. Note that to convert from base 16 to base 2 you need to convert first to base 10 and then base 2.
This function generate decimal number to any base from 2 to 36.(as like javascript)But you can Increase the base more than 36 just by adding new character in keys[] like lowercase["a","b"]
function toBase(num, radix = 10) { // only i64 numbers
var keys = ['🤢', '😃', 2, 3, 4, 5, 6, 7, 8, 9, "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
if (!(radix >= 2 && radix <= keys.length)) throw new RangeError("toBase() radix argument must be between 2 and " + keys.length)
if (num < 0) var isNegative = true
if (isNaN(num = Math.abs(+num))) return NaN
let output = [];
do {
let index = num % radix;
output.unshift(keys[index]);
num = Math.trunc(num / radix);
} while (num != 0);
if (isNegative) output.unshift('-')
return output.join("");
}
console.log(toBase("100",2))
Specify the radix you want to use as a parameter.
NOTE: This only works to convert from bases 2-36 to decimal and little values.
parseInt(string, radix)
parseInt("80", 10) // results in 80
parseInt("80", 16) // results in 128
// etc
About "little", parseInt("6f", 32) is fine (= 207), but any other little bigger will be also 207, 6f1, 6f11, ...
Well, I made a function that could translate from base 10 to any base. (This depends on how many strings you have in the array A, if it's more than that + 10 it'll run out of symbols), and I almost cried when I found out you could to it in less than 10 characters with that...
Add a bookmark and as URL insert this... I've done it the long but personal way. At least, mine can use a base which is higher than 36. You can add more symbols yourself, but if you want, I can make it for you...
var X = prompt("Choose your number");
var Y = prompt("Choose your base");
var Z = [];
var M = -1;
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
var B = function() {
for (i = X; 0 < i; i = Math.floor(i / Y)) {
if(i % Y >= 10) {
Z.push(A[i % Y - 10]);
} else {
Z.push(i % Y);
}
M = M + 1;
}
for (j = M; j >= 0; j--) {
document.write(Z[j]);
}
};
B(); // Call function
Usually I use this function to convert from different bases.
For example, it returns "11111111" for both cases:
convertBase("ff", 16, 2) or convertBase(0xFF, 16, 2)
var convertBase = function(val, base1, base2) {
if (typeof(val) == "number") {
return parseInt(String(val)).toString(base2);
} else {
return parseInt(val.toString(), base1).toString(base2)
};
}
I've written a function to convert a JavaScript string from one base to another base, with the original base and the new base specified as parameters.
function convertFromBaseToBase(str, fromBase, toBase){
var num = parseInt(str, fromBase);
return num.toString(toBase);
}
alert(convertFromBaseToBase(10, 2, 10));
This function converts a number from base 10, to an arbitrary base:
function to_base(base, num) {
const largest_power = ~~(Math.log(num) / Math.log(base));
const result = [];
for (let pow = largest_power; pow >= 0; pow--) {
const digit = ~~(num / base ** pow);
num -= digit * base ** pow;
result.push(digit);
}
return result;
}
to_base(2, 13) // [1, 1, 0, 1]
to_base(10, 458) // [4, 5, 8]
to_base(32, 1024) //Â [1, 0, 0]
to_base(32, 1023) //Â [31, 31]
which can be useful if you want to use weird bases along with weird char-set
Using the parseInt function:
var noInBase10 = parseInt('8F',16);
Check the complete JS code to convert into different base
/**
* Convert From/To Binary/Decimal/Hexadecimal in JavaScript
* https://gist.github.com/shamshul2007/
* Copyright 2012-2015, Shamshul <shamshul2007#gmail.com>
* Licensed under The MIT License
* http://www.opensource.org/licenses/mit-license
*/
(function(){
var ConvertBase = function (num) {
return {
from : function (baseFrom) {
return {
to : function (baseTo) {
return parseInt(num, baseFrom).toString(baseTo);
}
};
}
};
};
// binary to decimal
ConvertBase.bin2dec = function (num) {
return ConvertBase(num).from(2).to(10);
};
// binary to hexadecimal
ConvertBase.bin2hex = function (num) {
return ConvertBase(num).from(2).to(16);
};
// decimal to binary
ConvertBase.dec2bin = function (num) {
return ConvertBase(num).from(10).to(2);
};
// decimal to hexadecimal
ConvertBase.dec2hex = function (num) {
return ConvertBase(num).from(10).to(16);
};
// hexadecimal to binary
ConvertBase.hex2bin = function (num) {
return ConvertBase(num).from(16).to(2);
};
// hexadecimal to decimal
ConvertBase.hex2dec = function (num) {
return ConvertBase(num).from(16).to(10);
};
//Octal to Decimal
ConvertBase.oct2dec = function (num) {
return ConvertBase(num).from(8).to(10);
};
//Decimal to Octal
ConvertBase.dec2oct = function (num) {
return ConvertBase(num).from(10).to(8);
};
this.ConvertBase = ConvertBase;
})(this);
/*
* Usage example:
* ConvertBase.bin2dec('1111'); // '15'
* ConvertBase.dec2hex('82'); // '52'
* ConvertBase.hex2bin('e2'); // '11100010'
* ConvertBase.dec2bin('153'); // '10011001'
* ConvertBase.hex2dec('1FE4ED63D55FA51E'); //'2298222722903156000'
* ConvertBase.oct2dec('777'); //'511'
* ConvertBase.dec2oct('551'); //'1047'
*/
Try the following code, optimised from Slavik Meltser's post, implements BASE n conversions with all the radix combinations between Base2 and Base256. This code accepts three sorts of arguments to define source and destination number systems:
by number system radix (e.g. 8)
by number system convention name (e.g. 'Bitcoin')
by giving custom numerals as an argument (e.g. ['0123456789ABCDEF'])
You'll see that some number system numerals have been hard-coded inside the class and will be used as default when you pass the radix as an argument. (.e.g. 64) When no hard-coded numeral exists (e.g. 16), default numerals are assigned for all radixes ranging between Base2 and Base256, which becomes very clear in the self-test further below.
function BASE() {
/**
* BASE n converter doing all the radix combinations between Base2 and Base256
* #param {String} str input number
* #param {Number|String|Array} fromBase input number system radix (Number, e.g. 64), convention name (String, e.g. 'Bitcoin') or range (Array)
* #param {Number|String|Array} toBASE output number system radix (Number), convention name (String) or range (Array e.g. ['0123456789'])
* #return {String} output number
*/
this.convert = function (str, fromBase, toBASE)
{
if(typeof(fromBase)=='object') { this.fromSymbols = fromBase[0] } else this.fromSymbols = this.getsymbols(fromBase);
if(typeof(toBASE) =='object') { this.toSymbols = toBASE[0] } else this.toSymbols = this.getsymbols(toBASE);
fromBase = this.fromSymbols.length; toBASE = this.toSymbols.length;
// PARSE INPUT DIGITS ARRAY
for(var _a = [0], str = str.split(''); str.length > 0 && _a[_a.push(this.fromSymbols.indexOf(str.pop())) - 1] >= 0;);
var _d = _a.shift() + _a[_a.length-1]>=0 ? _a : null; if (_d === null) return null;
// BASE CONVERSION
for (var _n = 0,_a = [],_p = [1]; _n < _d.length; _n++) { _a = add(_a, mul(_d[_n], _p, toBASE), toBASE); _p = mul(fromBase, _p, toBASE) }
// PARSE OUTPUT DIGITS ARRAY
for (var _n = _a.length - 1, _o = ''; _n >= 0; _o += this.toSymbols[_a[_n--]]);
return _o.length==0?this.toSymbols[0]:_o;
}
this.symbols = {
32:function(){return this["base32hex"]},
36:["[0-9][A-Z]"],
45:function(){return this["qr-alnum"]},
58:function(){return this["Bitcoin"]},
64:["[A-Z][a-z][0-9]+/"],
85:function(){return this["RFC 1924"]},
91:["[A-Z][a-z][0-9]!#$%&()*+,./:;<=>?#[]^_`{|}~\""],
94:["[!-~]"],
"geohash": ["[0-9][b-h]jkmn[p-z]"], // base 32
"RFC 4648": ["[A-Z][2-7]"], // base 32
"base32hex": ["[0-9][A-V]"], // base 32
"qr-alnum":["[0-9][A-Z] $%*+-./:"], // base 45
"Bitcoin": ["[1-9][A-H]JKLMN[P-Z][a-k][m-z]"], // base 58
"RFC 1924": ["[0-9][A-Z][a-z]!#$%&()*+-;<=>?#^_`{|}~"] // base 85
}
this.getsymbols = function(index) {
if(typeof(this.symbols[index])=="undefined") this.symbols[index] = index<95?this.rng(index<64?"[0-9][A-Z][a-z]+":"[A-Z][a-z][0-9][!-/][:-#][[-`][{-~]").substring(0,index):this.rng("[\x00-\xff]").substring(256-index,256);
if(typeof(this.symbols[index])=="function") this.symbols[index] = this.symbols[index](); // process references
if(typeof(this.symbols[index])=="object") this.symbols[index] = this.rng(this.symbols[index][0]); // process range_replace
return this.symbols[index];
}
this.rng = function(_s) {
var _a = _s.match(/\[.-.\]/); if(_a==null) return _s; else { _a=[_a[0].charCodeAt(1),_a[0].charCodeAt(3)];
return this.rng(_s.replace(RegExp("\\[(\\x"+("0"+_a[0].toString(16)).slice(-2)+"-\\x"+_a[1].toString(16)+")\\]","g")
,String.fromCharCode(..." ".repeat(_a[1]-_a[0]+1).split("").map((_e,_i)=>_i+_a[0])) )) }
}
this.selftest = function() {
var _a={}; for(var _o in this.symbols) _a[_o] = this.getsymbols(_o).length; // built-in symbols
for(_o=2;_o<=95;_o++) _a[_o] = this.getsymbols(_o).length; _a[256]=256; // symbol range 2-95 + 256 (96-255 is similar)
var _s = "",_a = Object.keys(_a).sort(function(a,b){return _a[a]-_a[b]}); // sort merged list
for(var _i in _a) { // iterate number systems
_o = {fromBase:10, toBASE:_a[_i]}; var _r = this.convert("",10,_o.toBASE)
_s += "\r\n\oBASE.convert(n, '"+_o.fromBase+"', '"+_o.toBASE+"') ["+this.fromSymbols+"] ["+this.toSymbols+"]\r\n"
for(var _n=0;_n<(this.fromSymbols.length+2);_n++) { // iterate numbers
_r = this.convert(String(_n),_o.fromBase,_o.toBASE)
_s += _n+(String(_n)==this.convert(_r,_o.toBASE,_o.fromBase)?">":"?")+"["+_r+"] ";
}
}
return _s
}
var add = function(x, y, base) {
var _m = Math.max(x.length, y.length);
for(var _c = _n = 0,_r = []; _n < _m || _c; _c = Math.floor(_z / base)) {
var _z = _c + (_n < x.length ? x[_n] : 0) + (_n < y.length ? y[_n] : 0);
var _n = _r.push(_z % base);
}
return _r;
}
var mul = function(x, pow, base) {
for(var _r = x < 0 ? null : []; x > 0; x = x >> 1) {
if(x & 1) _r = add(_r, pow, base);
pow = add(pow, pow, base);
}
return _r;
}
}
Usage:
// quick test, convert from base45 to base32, using custom symbols for base85 and back to base45
var oBASE = new BASE();
var n = "THIS IS A NUMBER"; // Base 45 code = 'qr-alnum'
console.log(n); // Result: 'THIS IS A NUMBER'
var n = oBASE.convert(n,"qr-alnum",32); // Base 45 to Base 32 = 'base32hex'
console.log(n); // Result: '4ONI84LCTLJ1U08G1N'
var s85 = oBASE.rng("[0-9][a-z][A-Z].-:+=^!/*?&<>()[]{}#%$#"); // 32/Z85 custom symbols
var n = oBASE.convert(n,"base32hex",[s85]); // 'base2hex' to custom Base 85
console.log(n); // Result: 'fnaxrZP)?5d[DG'
var n = oBASE.convert(n,[s85],45); // Custom Base 85 to Base 45 = 'qr-alnum'
console.log(n); // Result: 'THIS IS A NUMBER'
function BASE(){this.convert=function(o,r,n){this.fromSymbols="object"==typeof r?r[0]:this.getsymbols(r),this.toSymbols="object"==typeof n?n[0]:this.getsymbols(n),r=this.fromSymbols.length,n=this.toSymbols.length;var i=[0];for(o=o.split("");o.length>0&&i[i.push(this.fromSymbols.indexOf(o.pop()))-1]>=0;);var h=i.shift()+i[i.length-1]>=0?i:null;if(null===h)return null;for(var e=0,l=(i=[],[1]);e<h.length;e++)i=t(i,s(h[e],l,n),n),l=s(r,l,n);e=i.length-1;for(var m="";e>=0;m+=this.toSymbols[i[e--]]);return 0==m.length?this.toSymbols[0]:m},this.symbols={32:function(){return this.base32hex},36:["[0-9][A-Z]"],45:function(){return this["qr-alnum"]},58:function(){return this.Bitcoin},64:["[A-Z][a-z][0-9]+/"],85:function(){return this["RFC 1924"]},91:['[A-Z][a-z][0-9]!#$%&()*+,./:;<=>?#[]^_`{|}~"'],94:["[!-~]"],geohash:["[0-9][b-h]jkmn[p-z]"],"RFC 4648":["[A-Z][2-7]"],base32hex:["[0-9][A-V]"],"qr-alnum":["[0-9][A-Z] $%*+-./:"],Bitcoin:["[1-9][A-H]JKLMN[P-Z][a-k][m-z]"],"RFC 1924":["[0-9][A-Z][a-z]!#$%&()*+-;<=>?#^_`{|}~"]},this.getsymbols=function(t){return void 0===this.symbols[t]&&(this.symbols[t]=t<95?this.rng(t<64?"[0-9][A-Z][a-z]+":"[A-Z][a-z][0-9][!-/][:-#][[-`][{-~]").substring(0,t):this.rng("[\0-ÿ]").substring(256-t,256)),"function"==typeof this.symbols[t]&&(this.symbols[t]=this.symbols[t]()),"object"==typeof this.symbols[t]&&(this.symbols[t]=this.rng(this.symbols[t][0])),this.symbols[t]},this.rng=function(t){var s=t.match(/\[.-.\]/);return null==s?t:(s=[s[0].charCodeAt(1),s[0].charCodeAt(3)],this.rng(t.replace(RegExp("\\[(\\x"+("0"+s[0].toString(16)).slice(-2)+"-\\x"+s[1].toString(16)+")\\]","g"),String.fromCharCode(..." ".repeat(s[1]-s[0]+1).split("").map((t,o)=>o+s[0])))))},this.selftest=function(){var t={};for(var s in this.symbols)t[s]=this.getsymbols(s).length;for(s=2;s<=95;s++)t[s]=this.getsymbols(s).length;t[256]=256;var o="";t=Object.keys(t).sort(function(s,o){return t[s]-t[o]});for(var r in t){s={fromBase:10,toBASE:t[r]};var n=this.convert("",10,s.toBASE);o+="\r\noBASE.convert(n, '"+s.fromBase+"', '"+s.toBASE+"') ["+this.fromSymbols+"] ["+this.toSymbols+"]\r\n";for(var i=0;i<this.fromSymbols.length+2;i++)n=this.convert(String(i),s.fromBase,s.toBASE),o+=i+(String(i)==this.convert(n,s.toBASE,s.fromBase)?">":"?")+"["+n+"] "}return o};var t=function(t,s,o){for(var r=Math.max(t.length,s.length),n=e=0,i=[];e<r||n;n=Math.floor(h/o))var h=n+(e<t.length?t[e]:0)+(e<s.length?s[e]:0),e=i.push(h%o);return i},s=function(s,o,r){for(var n=s<0?null:[];s>0;s>>=1)1&s&&(n=t(n,o,r)),o=t(o,o,r);return n}}
Self-Test:
// quick test, convert from base45 to base32, using custom symbols for base85 and back to base45
var oBASE = new BASE();
console.log(oBASE.selftest())
function BASE(){this.convert=function(o,r,n){this.fromSymbols="object"==typeof r?r[0]:this.getsymbols(r),this.toSymbols="object"==typeof n?n[0]:this.getsymbols(n),r=this.fromSymbols.length,n=this.toSymbols.length;var i=[0];for(o=o.split("");o.length>0&&i[i.push(this.fromSymbols.indexOf(o.pop()))-1]>=0;);var h=i.shift()+i[i.length-1]>=0?i:null;if(null===h)return null;for(var e=0,l=(i=[],[1]);e<h.length;e++)i=t(i,s(h[e],l,n),n),l=s(r,l,n);e=i.length-1;for(var m="";e>=0;m+=this.toSymbols[i[e--]]);return 0==m.length?this.toSymbols[0]:m},this.symbols={32:function(){return this.base32hex},36:["[0-9][A-Z]"],45:function(){return this["qr-alnum"]},58:function(){return this.Bitcoin},64:["[A-Z][a-z][0-9]+/"],85:function(){return this["RFC 1924"]},91:['[A-Z][a-z][0-9]!#$%&()*+,./:;<=>?#[]^_`{|}~"'],94:["[!-~]"],geohash:["[0-9][b-h]jkmn[p-z]"],"RFC 4648":["[A-Z][2-7]"],base32hex:["[0-9][A-V]"],"qr-alnum":["[0-9][A-Z] $%*+-./:"],Bitcoin:["[1-9][A-H]JKLMN[P-Z][a-k][m-z]"],"RFC 1924":["[0-9][A-Z][a-z]!#$%&()*+-;<=>?#^_`{|}~"]},this.getsymbols=function(t){return void 0===this.symbols[t]&&(this.symbols[t]=t<95?this.rng(t<64?"[0-9][A-Z][a-z]+":"[A-Z][a-z][0-9][!-/][:-#][[-`][{-~]").substring(0,t):this.rng("[\0-ÿ]").substring(256-t,256)),"function"==typeof this.symbols[t]&&(this.symbols[t]=this.symbols[t]()),"object"==typeof this.symbols[t]&&(this.symbols[t]=this.rng(this.symbols[t][0])),this.symbols[t]},this.rng=function(t){var s=t.match(/\[.-.\]/);return null==s?t:(s=[s[0].charCodeAt(1),s[0].charCodeAt(3)],this.rng(t.replace(RegExp("\\[(\\x"+("0"+s[0].toString(16)).slice(-2)+"-\\x"+s[1].toString(16)+")\\]","g"),String.fromCharCode(..." ".repeat(s[1]-s[0]+1).split("").map((t,o)=>o+s[0])))))},this.selftest=function(){var t={};for(var s in this.symbols)t[s]=this.getsymbols(s).length;for(s=2;s<=95;s++)t[s]=this.getsymbols(s).length;t[256]=256;var o="";t=Object.keys(t).sort(function(s,o){return t[s]-t[o]});for(var r in t){s={fromBase:10,toBASE:t[r]};var n=this.convert("",10,s.toBASE);o+="\r\noBASE.convert(n, '"+s.fromBase+"', '"+s.toBASE+"') ["+this.fromSymbols+"] ["+this.toSymbols+"]\r\n";for(var i=0;i<this.fromSymbols.length+2;i++)n=this.convert(String(i),s.fromBase,s.toBASE),o+=i+(String(i)==this.convert(n,s.toBASE,s.fromBase)?">":"?")+"["+n+"] "}return o};var t=function(t,s,o){for(var r=Math.max(t.length,s.length),n=e=0,i=[];e<r||n;n=Math.floor(h/o))var h=n+(e<t.length?t[e]:0)+(e<s.length?s[e]:0),e=i.push(h%o);return i},s=function(s,o,r){for(var n=s<0?null:[];s>0;s>>=1)1&s&&(n=t(n,o,r)),o=t(o,o,r);return n}}
to convert numbers into different bases in JavaScript or typescript using the following ways.
function binary(number) {
console.log((number >>> 0).toString(2)); //base 2 for binary
}
binary(-7);
function octal(number) {
console.log(number.toString(8)); //base 8 for octal
}
octal(15);
function hex(number) {
console.log(number.toString(16)); //base 16 for hex
}
hex(15);
here in the binary function, you can use number.toString(2) function, but the problem occurs when representing negative numbers. so that you can use the unsigned right shift bitwise operator (>>>) to fix this issue.
You can also convert number in hexadecimal to decimal as follows:
var a="8F";
var b=a.split("");
var result=0;var hex_multiplier=1;
for(var i=0;i<b.length;i++){
result +=parseInt(b[i],16)*hex_multiplier;
hex_multiplier *=16;
}
console.log(result);
where you can change a with any hexadecimal number and get the result in decimal form.
You can use JavaScript's built-in integer literals for some scenarios:
function binaryToDecimal(binaryString) {
return Number('0b' + binaryString.replace('-', '')) * signOf(binaryString);;
}
function octalToDecimal(octalString) {
return Number('0o' + octalString.replace('-', '')) * signOf(octalString);
}
function hexToDecimal(hexString) {
return Number('0x' + hexString.replace('-', '')) * signOf(hexString);
}
function signOf(n) {
return n.trim()[0] == '-' ? -1 : 1;
}
console.log(binaryToDecimal('-0101'),
octalToDecimal('-052171'),
hexToDecimal('deadbeef'));
This code converts a number to an arbitrary-large base, outputting an array of digits.
function convertBase(num, base) {
var result = [];
while(num >= 1) {
result.unshift(num % base);
num = Math.floor(num / base);
}
return result;
}
console.log(convertBase(100, 12)); // [8, 4]
console.log(convertBase(5114, 64)); // [1, 15, 58]
TypeScript Implementation that supports decimal and int:
class Digit {
private readonly digitMap: Map<string, number>;
constructor(readonly digits: string, readonly maxDigits = 10) {
this.digitMap = new Map<string, number>();
for (let i = 0; i < digits.length; i += 1) {
if (digits[i] === ".") {
throw new TypeError(`Digits should not contain the "." mark.`);
}
if (this.digitMap.has(digits[i])) {
throw new TypeError(`Duplicated digit character.`);
}
this.digitMap.set(digits[i], i);
}
}
to = (x: number) => {
const int = Math.floor(x);
const dec = x - int;
let intRemains = int;
let intResult = "";
while (true) {
intResult = this.digits[intRemains % this.digits.length] + intResult;
intRemains = Math.floor(intRemains / this.digits.length);
if (intRemains === 0) break;
}
if (dec > 0) {
let decRemains = dec;
let decResult = "";
for (let i = 0; i < this.maxDigits; i += 1) {
const stepCache = decRemains * this.digits.length;
const decInt = Math.floor(stepCache);
decResult = decResult + this.digits[decInt];
decRemains = stepCache - decInt;
if (decRemains === 0) break;
}
if (decResult === "0") return intResult;
return intResult + "." + decResult;
}
return intResult;
};
from = (x: string) => {
const splitted = x.split(".");
if (splitted.length > 2) return Number.NaN;
const [int, dec] = splitted;
let result = 0;
for (let i = 0; i < int.length; i += 1) {
const digit = int[int.length - i - 1];
const oct = this.digitMap.get(digit);
if (oct === undefined) return Number.NaN;
result += oct * Math.pow(this.digits.length, i);
}
if (dec) {
for (let i = 0; i < dec.length; i += 1) {
const digit = dec[i];
const oct = this.digitMap.get(digit);
if (oct === undefined) return Number.NaN;
result += oct * Math.pow(this.digits.length, 0 - i - 1);
}
}
return result;
};
}
Here're the example about how to use it:
Creating the converter:
const d = new Digit("0123456789");
Convert a number to string:
d.to(1.2345);
Convert a string to number:
d.from("1.2345");
You can also set the second parameter to control the maximum number of decimal places, for example:
const d0 = new Digit("abcdABCD", 10);
d0.to(0.96);
// a.DBdAbcbDcD
const d1 = new Digit("abcdABCD", 20);
d1.to(0.96);
// a.DBdAbcbDcDacAdCBC
Monkey patched Number prototype for all radixes up to and including 64
( inspired by and derived from #nirvana's answer )
NumberToStringPatched.__patched = NumberToStringPatched;
if (Number.prototype.toString.__patched!==NumberToStringPatched) {
NumberToStringPatched.__unpatched = Number.prototype.toString;
Number.prototype.toString = NumberToStringPatched;
}
NumberParseIntPatched.__patched = NumberParseIntPatched;
if (Number.parseInt.__patched!==NumberParseIntPatched) {
NumberParseIntPatched.__unpatched = Number.parseInt;
Number.parseInt = NumberParseIntPatched;
}
function NumberToStringPatched(base=10) {
if (base<33||base>64) return NumberToStringPatched.__unpatched.call(this,base);
return convertToBase(this,base);
}
function NumberParseIntPatched(str,base=10) {
if (base<33||base>64) return NumberParseIntPatched.__unpatched.call(this,str,base);
return convertFromBase(str,base);
}
const numberCharSet=(()=>{
let chars = "0123456789";
for (let c='a';c<='z';c=String.fromCharCode(c.charCodeAt(0)+1)) {
chars+=c;
}
for (let c='A';c<='Z';c=String.fromCharCode(c.charCodeAt(0)+1)) {
chars+=c;
}
return (chars+'_$').split('');
})();
function convertToBase(num, base) {
var result = '';
while(num >= 1) {
result = numberCharSet[num % base]+result;
num = Math.floor(num / base);
}
return result;
}
function convertFromBase(str, base) {
let charset = numberCharSet.slice(0,base);
if (typeof str==='number') str=str.toString(base);
if (base <= 26) str=str.toLowerCase();
let digits = str.split('').map(function(c){
let x = charset.indexOf(c);
if (x<0) throw new Error("invalid digit for given radix "+base+': '+c);
return x;
});
let result = digits.shift();
while (digits.length) {
result=(result*base)+digits.shift();
}
return result;
}
for (let i = 0;i<64;i++) {
console.log(i.toString(64));
}
console.log(9000);
console.log(9 * 10 * 10 * 10);
console.log(0xf000);
console.log(15 * 16 * 16 * 16);
console.log(Number.parseInt('$000',64));
console.log(63 * 64 * 64 * 64);
I am writing this answer simply because I was kinda stupid to understand the difference between parseInt and .toString().
Here is the difference
parseInt
parseInt(str, base) will convert the str to an Integer and base here is used to tell parseInt which base the str is in. I thought the base here was what the str would get converted to. But thats not true. parseInt is just used to convert a number in any base to an integer in base10.
.toString()
number.toString(base) is used to convert the number into a number with base base and it assumes that number is in Integer form. So if the number is in hex format and you want to convert it to binary you need to convert the number first to Integer using parseInt and then you can use this function to change the base.
Hope this helps if you are as stupid as me. :)
Your Own recursion method for creating base2 conversions.
As mentioned by the users above
let n = 13; console.log(n.toString(2)); will result in 13 conversion from base 10 to base 2.
But in case if you want to program the same. I have written a recursive method to do the same. which just simply divide by 2 and then count remainders.
// #author Tarandeep Singh :: Created recursive converter from base 10 to base 2
// #date : 2017-04-11
// Convert Base 10 to Base 2, We should reverse the output
// For Example base10to2(10) = "0101" just do res = base10to2(10).split('').reverse().join();
function base10to2(val, res = '') {
if (val >= 2) {
res += '' + val % 2;
return base10to2(val = Math.floor(val / 2), res);
} else {
res += '' + 1
return res;
}
}
let n = 13;
var result = base10to2(n).split('').reverse().join();
document.write(`Converting ${n} into Base2 is ${result}`);
In JavaScript, how can I convert a sequence of numbers in an array to a range of numbers? In other words, I want to express consecutive occurring integers (no gaps) as hyphenated ranges.
[2,3,4,5,10,18,19,20] would become [2-5,10,18-20]
[1,6,7,9,10,12] would become [1,6-7,9-10,12]
[3,5,99] would remain [3,5,99]
[5,6,7,8,9,10,11] would become [5-11]
Here is an algorithm that I made some time ago, originally written for C#, now I ported it to JavaScript:
function getRanges(array) {
var ranges = [], rstart, rend;
for (var i = 0; i < array.length; i++) {
rstart = array[i];
rend = rstart;
while (array[i + 1] - array[i] == 1) {
rend = array[i + 1]; // increment the index if the numbers sequential
i++;
}
ranges.push(rstart == rend ? rstart+'' : rstart + '-' + rend);
}
return ranges;
}
getRanges([2,3,4,5,10,18,19,20]);
// returns ["2-5", "10", "18-20"]
getRanges([1,2,3,5,7,9,10,11,12,14 ]);
// returns ["1-3", "5", "7", "9-12", "14"]
getRanges([1,2,3,4,5,6,7,8,9,10])
// returns ["1-10"]
Just having fun with solution from CMS :
function getRanges (array) {
for (var ranges = [], rend, i = 0; i < array.length;) {
ranges.push ((rend = array[i]) + ((function (rstart) {
while (++rend === array[++i]);
return --rend === rstart;
})(rend) ? '' : '-' + rend));
}
return ranges;
}
Very nice question: here's my attempt:
function ranges(numbers){
var sorted = numbers.sort(function(a,b){return a-b;});
var first = sorted.shift();
return sorted.reduce(function(ranges, num){
if(num - ranges[0][1] <= 1){
ranges[0][1] = num;
} else {
ranges.unshift([num,num]);
}
return ranges;
},[[first,first]]).map(function(ranges){
return ranges[0] === ranges[1] ?
ranges[0].toString() : ranges.join('-');
}).reverse();
}
Demo on JSFiddler
I needed TypeScript code today to solve this very problem -- many years after the OP -- and decided to try a version written in a style more functional than the other answers here. Of course, only the parameter and return type annotations distinguish this code from standard ES6 JavaScript.
function toRanges(values: number[],
separator = '\u2013'): string[] {
return values
.slice()
.sort((p, q) => p - q)
.reduce((acc, cur, idx, src) => {
if ((idx > 0) && ((cur - src[idx - 1]) === 1))
acc[acc.length - 1][1] = cur;
else acc.push([cur]);
return acc;
}, [])
.map(range => range.join(separator));
}
Note that slice is necessary because sort sorts in place and we can't change the original array.
Here's my take on this...
function getRanges(input) {
//setup the return value
var ret = [], ary, first, last;
//copy and sort
var ary = input.concat([]);
ary.sort(function(a,b){
return Number(a) - Number(b);
});
//iterate through the array
for (var i=0; i<ary.length; i++) {
//set the first and last value, to the current iteration
first = last = ary[i];
//while within the range, increment
while (ary[i+1] == last+1) {
last++;
i++;
}
//push the current set into the return value
ret.push(first == last ? first : first + "-" + last);
}
//return the response array.
return ret;
}
Using ES6, a solution is:
function display ( vector ) { // assume vector sorted in increasing order
// display e.g.vector [ 2,4,5,6,9,11,12,13,15 ] as "2;4-6;9;11-13;15"
const l = vector.length - 1; // last valid index of vector array
// map [ 2,4,5,6,9,11,12,13,15 ] into array of strings (quote ommitted)
// --> [ "2;", "4-", "-", "6;", "9;", "11-", "-", "13;", "15;" ]
vector = vector.map ( ( n, i, v ) => // n is current number at index i of vector v
i < l && v [ i + 1 ] - n === 1 ? // next number is adjacent ?
`${ i > 0 && n - v [ i - 1 ] === 1 ? "" : n }-` :
`${ n };`
);
return vector.join ( "" ). // concatenate all strings in vector array
replace ( /-+/g, "-" ). // replace multiple dashes by single dash
slice ( 0, -1 ); // remove trailing ;
}
If you want to add extra spaces for readability, just add extra calls to string.prototype.replace().
If the input vector is not sorted, you can add the following line right after the opening brace of the display() function:
vector.sort ( ( a, b ) => a - b ); // sort vector in place, in increasing order.
Note that this could be improved to avoid testing twice for integer adjacentness (adjacenthood? I'm not a native English speaker;-).
And of course, if you don't want a single string as output, split it with ";".
Rough outline of the process is as follows:
Create an empty array called ranges
For each value in sorted input array
If ranges is empty then insert the item {min: value, max: value}
Else if max of last item in ranges and the current value are consecutive then set max of last item in ranges = value
Else insert the item {min: value, max: value}
Format the ranges array as desired e.g. by combining min and max if same
The following code uses Array.reduce and simplifies the logic by combining step 2.1 and 2.3.
function arrayToRange(array) {
return array
.slice()
.sort(function(a, b) {
return a - b;
})
.reduce(function(ranges, value) {
var lastIndex = ranges.length - 1;
if (lastIndex === -1 || ranges[lastIndex].max !== value - 1) {
ranges.push({ min: value, max: value });
} else {
ranges[lastIndex].max = value;
}
return ranges;
}, [])
.map(function(range) {
return range.min !== range.max ? range.min + "-" + range.max : range.min.toString();
});
}
console.log(arrayToRange([2, 3, 4, 5, 10, 18, 19, 20]));
If you simply want a string that represents a range, then you'd find the mid-point of your sequence, and that becomes your middle value (10 in your example). You'd then grab the first item in the sequence, and the item that immediately preceded your mid-point, and build your first-sequence representation. You'd follow the same procedure to get your last item, and the item that immediately follows your mid-point, and build your last-sequence representation.
// Provide initial sequence
var sequence = [1,2,3,4,5,6,7,8,9,10];
// Find midpoint
var midpoint = Math.ceil(sequence.length/2);
// Build first sequence from midpoint
var firstSequence = sequence[0] + "-" + sequence[midpoint-2];
// Build second sequence from midpoint
var lastSequence = sequence[midpoint] + "-" + sequence[sequence.length-1];
// Place all new in array
var newArray = [firstSequence,midpoint,lastSequence];
alert(newArray.join(",")); // 1-4,5,6-10
Demo Online: http://jsbin.com/uvahi/edit
; For all cells of the array
;if current cell = prev cell + 1 -> range continues
;if current cell != prev cell + 1 -> range ended
int[] x = [2,3,4,5,10,18,19,20]
string output = '['+x[0]
bool range = false; --current range
for (int i = 1; i > x[].length; i++) {
if (x[i+1] = [x]+1) {
range = true;
} else { //not sequential
if range = true
output = output || '-'
else
output = output || ','
output.append(x[i]','||x[i+1])
range = false;
}
}
Something like that.
An adaptation of CMS's javascript solution for Cold Fusion
It does sort the list first so that 1,3,2,4,5,8,9,10 (or similar) properly converts to 1-5,8-10.
<cfscript>
function getRanges(nArr) {
arguments.nArr = listToArray(listSort(arguments.nArr,"numeric"));
var ranges = [];
var rstart = "";
var rend = "";
for (local.i = 1; i <= ArrayLen(arguments.nArr); i++) {
rstart = arguments.nArr[i];
rend = rstart;
while (i < ArrayLen(arguments.nArr) and (val(arguments.nArr[i + 1]) - val(arguments.nArr[i])) == 1) {
rend = val(arguments.nArr[i + 1]); // increment the index if the numbers sequential
i++;
}
ArrayAppend(ranges,rstart == rend ? rstart : rstart & '-' & rend);
}
return arraytolist(ranges);
}
</cfscript>
Tiny ES6 module for you guys. It accepts a function to determine when we must break the sequence (breakDetectorFunc param - default is the simple thing for integer sequence input).
NOTICE: since input is abstract - there's no auto-sorting before processing, so if your sequence isn't sorted - do it prior to calling this module
function defaultIntDetector(a, b){
return Math.abs(b - a) > 1;
}
/**
* #param {Array} valuesArray
* #param {Boolean} [allArraysResult=false] if true - [1,2,3,7] will return [[1,3], [7,7]]. Otherwise [[1.3], 7]
* #param {SequenceToIntervalsBreakDetector} [breakDetectorFunc] must return true if value1 and value2 can't be in one sequence (if we need a gap here)
* #return {Array}
*/
const sequenceToIntervals = function (valuesArray, allArraysResult, breakDetectorFunc) {
if (!breakDetectorFunc){
breakDetectorFunc = defaultIntDetector;
}
if (typeof(allArraysResult) === 'undefined'){
allArraysResult = false;
}
const intervals = [];
let from = 0, to;
if (valuesArray instanceof Array) {
const cnt = valuesArray.length;
for (let i = 0; i < cnt; i++) {
to = i;
if (i < cnt - 1) { // i is not last (to compare to next)
if (breakDetectorFunc(valuesArray[i], valuesArray[i + 1])) {
// break
appendLastResult();
}
}
}
appendLastResult();
} else {
throw new Error("input is not an Array");
}
function appendLastResult(){
if (isFinite(from) && isFinite(to)) {
const vFrom = valuesArray[from];
const vTo = valuesArray[to];
if (from === to) {
intervals.push(
allArraysResult
? [vFrom, vTo] // same values array item
: vFrom // just a value, no array
);
} else if (Math.abs(from - to) === 1) { // sibling items
if (allArraysResult) {
intervals.push([vFrom, vFrom]);
intervals.push([vTo, vTo]);
} else {
intervals.push(vFrom, vTo);
}
} else {
intervals.push([vFrom, vTo]); // true interval
}
from = to + 1;
}
}
return intervals;
};
module.exports = sequenceToIntervals;
/** #callback SequenceToIntervalsBreakDetector
#param value1
#param value2
#return bool
*/
first argument is the input sequence sorted array, second is a boolean flag controlling the output mode: if true - single item (outside the intervals) will be returned as arrays anyway: [1,7],[9,9],[10,10],[12,20], otherwise single items returned as they appear in the input array
for your sample input
[2,3,4,5,10,18,19,20]
it will return:
sequenceToIntervals([2,3,4,5,10,18,19,20], true) // [[2,5], [10,10], [18,20]]
sequenceToIntervals([2,3,4,5,10,18,19,20], false) // [[2,5], 10, [18,20]]
sequenceToIntervals([2,3,4,5,10,18,19,20]) // [[2,5], 10, [18,20]]
Here's a version in Coffeescript
getRanges = (array) ->
ranges = []
rstart
rend
i = 0
while i < array.length
rstart = array[i]
rend = rstart
while array[i + 1] - array[i] is 1
rend = array[i + 1] # increment the index if the numbers sequential
i = i + 1
if rstart == rend
ranges.push rstart + ''
else
ranges.push rstart + '-' + rend
i = i + 1
return ranges
I've written my own method that's dependent on Lo-Dash, but doesn't just give you back an array of ranges, rather, it just returns an array of range groups.
[1,2,3,4,6,8,10] becomes:
[[1,2,3,4],[6,8,10]]
http://jsfiddle.net/mberkom/ufVey/
I would like to convert numbers between different bases, such as hexadecimal and decimal.
Example: How do you convert hexadecimal 8F to decimal?
The API
To convert to a number from a hex string:
parseInt(string, radix)
string: Required. The string to be parsed
radix: Optional. A number (from 2 to 36) that represents the numeral system to be used
To convert from a number to a hex string:
NumberObject.toString(radix)
radix: Optional. Specifies the base radix you would like the number displayed as.
Example radix values:
2 - The number will show as a binary value
8 - The number will show as an octal value
16 - The number will show as an hexadecimal value
Example Usage
Integer value to hex:
var i = 10;
console.log( i.toString(16) );
Hex string to integer value:
var h = "a";
console.log( parseInt(h, 16) );
Integer value to decimal:
var d = 16;
console.log( d.toString(10) );
Update 2023-01-05: Now supports large numbers and floats via https://github.com/ryansmith94/baseroo
I came to this post needing to convert from base 10 to 62 and vice-versa. Whilst the solutions here are great, parseInt and toString only support base 2 to 36. So if anyone finds themselves in a similar position to me needing base 2 to 62, I've pasted my solution below.
function convertBase(value, from_base, to_base) {
var range = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/'.split('');
var from_range = range.slice(0, from_base);
var to_range = range.slice(0, to_base);
var dec_value = value.split('').reverse().reduce(function (carry, digit, index) {
if (from_range.indexOf(digit) === -1) throw new Error('Invalid digit `'+digit+'` for base '+from_base+'.');
return carry += from_range.indexOf(digit) * (Math.pow(from_base, index));
}, 0);
var new_value = '';
while (dec_value > 0) {
new_value = to_range[dec_value % to_base] + new_value;
dec_value = (dec_value - (dec_value % to_base)) / to_base;
}
return new_value || '0';
}
You may try the following code, which also supports arbitrary precision numbers (larger than 2^53).
function convertBase(str, fromBase, toBase) {
const DIGITS = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ+/";
const add = (x, y, base) => {
let z = [];
const n = Math.max(x.length, y.length);
let carry = 0;
let i = 0;
while (i < n || carry) {
const xi = i < x.length ? x[i] : 0;
const yi = i < y.length ? y[i] : 0;
const zi = carry + xi + yi;
z.push(zi % base);
carry = Math.floor(zi / base);
i++;
}
return z;
}
const multiplyByNumber = (num, x, base) => {
if (num < 0) return null;
if (num == 0) return [];
let result = [];
let power = x;
while (true) {
num & 1 && (result = add(result, power, base));
num = num >> 1;
if (num === 0) break;
power = add(power, power, base);
}
return result;
}
const parseToDigitsArray = (str, base) => {
const digits = str.split('');
let arr = [];
for (let i = digits.length - 1; i >= 0; i--) {
const n = DIGITS.indexOf(digits[i])
if (n == -1) return null;
arr.push(n);
}
return arr;
}
const digits = parseToDigitsArray(str, fromBase);
if (digits === null) return null;
let outArray = [];
let power = [1];
for (let i = 0; i < digits.length; i++) {
digits[i] && (outArray = add(outArray, multiplyByNumber(digits[i], power, toBase), toBase));
power = multiplyByNumber(fromBase, power, toBase);
}
let out = '';
for (let i = outArray.length - 1; i >= 0; i--)
out += DIGITS[outArray[i]];
return out;
}
Usage:
console.log(convertBase("5a2a9c826c75045be9ba8fbffc80c6f25a2a9c826c75045be9ba8fbffc80c6f2",16,64));
// Returns: 5EGD89ItghrWrGfL/O0NL9qaFO2r7k4m+CWzX/YwcrO
console.log(convertBase("5EGD89ItghrWrGfL/O0NL9qaFO2r7k4m+CWzX/YwcrO",64,16));
// Returns: 5a2a9c826c75045be9ba8fbffc80c6f25a2a9c826c75045be9ba8fbffc80c6f2
The basic code has been found here, I have a bit improved it to also support up to base 64.
The following diagram might help. Note that to convert from base 16 to base 2 you need to convert first to base 10 and then base 2.
This function generate decimal number to any base from 2 to 36.(as like javascript)But you can Increase the base more than 36 just by adding new character in keys[] like lowercase["a","b"]
function toBase(num, radix = 10) { // only i64 numbers
var keys = ['🤢', '😃', 2, 3, 4, 5, 6, 7, 8, 9, "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
if (!(radix >= 2 && radix <= keys.length)) throw new RangeError("toBase() radix argument must be between 2 and " + keys.length)
if (num < 0) var isNegative = true
if (isNaN(num = Math.abs(+num))) return NaN
let output = [];
do {
let index = num % radix;
output.unshift(keys[index]);
num = Math.trunc(num / radix);
} while (num != 0);
if (isNegative) output.unshift('-')
return output.join("");
}
console.log(toBase("100",2))
Specify the radix you want to use as a parameter.
NOTE: This only works to convert from bases 2-36 to decimal and little values.
parseInt(string, radix)
parseInt("80", 10) // results in 80
parseInt("80", 16) // results in 128
// etc
About "little", parseInt("6f", 32) is fine (= 207), but any other little bigger will be also 207, 6f1, 6f11, ...
Well, I made a function that could translate from base 10 to any base. (This depends on how many strings you have in the array A, if it's more than that + 10 it'll run out of symbols), and I almost cried when I found out you could to it in less than 10 characters with that...
Add a bookmark and as URL insert this... I've done it the long but personal way. At least, mine can use a base which is higher than 36. You can add more symbols yourself, but if you want, I can make it for you...
var X = prompt("Choose your number");
var Y = prompt("Choose your base");
var Z = [];
var M = -1;
var A = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"];
var B = function() {
for (i = X; 0 < i; i = Math.floor(i / Y)) {
if(i % Y >= 10) {
Z.push(A[i % Y - 10]);
} else {
Z.push(i % Y);
}
M = M + 1;
}
for (j = M; j >= 0; j--) {
document.write(Z[j]);
}
};
B(); // Call function
Usually I use this function to convert from different bases.
For example, it returns "11111111" for both cases:
convertBase("ff", 16, 2) or convertBase(0xFF, 16, 2)
var convertBase = function(val, base1, base2) {
if (typeof(val) == "number") {
return parseInt(String(val)).toString(base2);
} else {
return parseInt(val.toString(), base1).toString(base2)
};
}
I've written a function to convert a JavaScript string from one base to another base, with the original base and the new base specified as parameters.
function convertFromBaseToBase(str, fromBase, toBase){
var num = parseInt(str, fromBase);
return num.toString(toBase);
}
alert(convertFromBaseToBase(10, 2, 10));
This function converts a number from base 10, to an arbitrary base:
function to_base(base, num) {
const largest_power = ~~(Math.log(num) / Math.log(base));
const result = [];
for (let pow = largest_power; pow >= 0; pow--) {
const digit = ~~(num / base ** pow);
num -= digit * base ** pow;
result.push(digit);
}
return result;
}
to_base(2, 13) // [1, 1, 0, 1]
to_base(10, 458) // [4, 5, 8]
to_base(32, 1024) //Â [1, 0, 0]
to_base(32, 1023) //Â [31, 31]
which can be useful if you want to use weird bases along with weird char-set
Using the parseInt function:
var noInBase10 = parseInt('8F',16);
Check the complete JS code to convert into different base
/**
* Convert From/To Binary/Decimal/Hexadecimal in JavaScript
* https://gist.github.com/shamshul2007/
* Copyright 2012-2015, Shamshul <shamshul2007#gmail.com>
* Licensed under The MIT License
* http://www.opensource.org/licenses/mit-license
*/
(function(){
var ConvertBase = function (num) {
return {
from : function (baseFrom) {
return {
to : function (baseTo) {
return parseInt(num, baseFrom).toString(baseTo);
}
};
}
};
};
// binary to decimal
ConvertBase.bin2dec = function (num) {
return ConvertBase(num).from(2).to(10);
};
// binary to hexadecimal
ConvertBase.bin2hex = function (num) {
return ConvertBase(num).from(2).to(16);
};
// decimal to binary
ConvertBase.dec2bin = function (num) {
return ConvertBase(num).from(10).to(2);
};
// decimal to hexadecimal
ConvertBase.dec2hex = function (num) {
return ConvertBase(num).from(10).to(16);
};
// hexadecimal to binary
ConvertBase.hex2bin = function (num) {
return ConvertBase(num).from(16).to(2);
};
// hexadecimal to decimal
ConvertBase.hex2dec = function (num) {
return ConvertBase(num).from(16).to(10);
};
//Octal to Decimal
ConvertBase.oct2dec = function (num) {
return ConvertBase(num).from(8).to(10);
};
//Decimal to Octal
ConvertBase.dec2oct = function (num) {
return ConvertBase(num).from(10).to(8);
};
this.ConvertBase = ConvertBase;
})(this);
/*
* Usage example:
* ConvertBase.bin2dec('1111'); // '15'
* ConvertBase.dec2hex('82'); // '52'
* ConvertBase.hex2bin('e2'); // '11100010'
* ConvertBase.dec2bin('153'); // '10011001'
* ConvertBase.hex2dec('1FE4ED63D55FA51E'); //'2298222722903156000'
* ConvertBase.oct2dec('777'); //'511'
* ConvertBase.dec2oct('551'); //'1047'
*/
Try the following code, optimised from Slavik Meltser's post, implements BASE n conversions with all the radix combinations between Base2 and Base256. This code accepts three sorts of arguments to define source and destination number systems:
by number system radix (e.g. 8)
by number system convention name (e.g. 'Bitcoin')
by giving custom numerals as an argument (e.g. ['0123456789ABCDEF'])
You'll see that some number system numerals have been hard-coded inside the class and will be used as default when you pass the radix as an argument. (.e.g. 64) When no hard-coded numeral exists (e.g. 16), default numerals are assigned for all radixes ranging between Base2 and Base256, which becomes very clear in the self-test further below.
function BASE() {
/**
* BASE n converter doing all the radix combinations between Base2 and Base256
* #param {String} str input number
* #param {Number|String|Array} fromBase input number system radix (Number, e.g. 64), convention name (String, e.g. 'Bitcoin') or range (Array)
* #param {Number|String|Array} toBASE output number system radix (Number), convention name (String) or range (Array e.g. ['0123456789'])
* #return {String} output number
*/
this.convert = function (str, fromBase, toBASE)
{
if(typeof(fromBase)=='object') { this.fromSymbols = fromBase[0] } else this.fromSymbols = this.getsymbols(fromBase);
if(typeof(toBASE) =='object') { this.toSymbols = toBASE[0] } else this.toSymbols = this.getsymbols(toBASE);
fromBase = this.fromSymbols.length; toBASE = this.toSymbols.length;
// PARSE INPUT DIGITS ARRAY
for(var _a = [0], str = str.split(''); str.length > 0 && _a[_a.push(this.fromSymbols.indexOf(str.pop())) - 1] >= 0;);
var _d = _a.shift() + _a[_a.length-1]>=0 ? _a : null; if (_d === null) return null;
// BASE CONVERSION
for (var _n = 0,_a = [],_p = [1]; _n < _d.length; _n++) { _a = add(_a, mul(_d[_n], _p, toBASE), toBASE); _p = mul(fromBase, _p, toBASE) }
// PARSE OUTPUT DIGITS ARRAY
for (var _n = _a.length - 1, _o = ''; _n >= 0; _o += this.toSymbols[_a[_n--]]);
return _o.length==0?this.toSymbols[0]:_o;
}
this.symbols = {
32:function(){return this["base32hex"]},
36:["[0-9][A-Z]"],
45:function(){return this["qr-alnum"]},
58:function(){return this["Bitcoin"]},
64:["[A-Z][a-z][0-9]+/"],
85:function(){return this["RFC 1924"]},
91:["[A-Z][a-z][0-9]!#$%&()*+,./:;<=>?#[]^_`{|}~\""],
94:["[!-~]"],
"geohash": ["[0-9][b-h]jkmn[p-z]"], // base 32
"RFC 4648": ["[A-Z][2-7]"], // base 32
"base32hex": ["[0-9][A-V]"], // base 32
"qr-alnum":["[0-9][A-Z] $%*+-./:"], // base 45
"Bitcoin": ["[1-9][A-H]JKLMN[P-Z][a-k][m-z]"], // base 58
"RFC 1924": ["[0-9][A-Z][a-z]!#$%&()*+-;<=>?#^_`{|}~"] // base 85
}
this.getsymbols = function(index) {
if(typeof(this.symbols[index])=="undefined") this.symbols[index] = index<95?this.rng(index<64?"[0-9][A-Z][a-z]+":"[A-Z][a-z][0-9][!-/][:-#][[-`][{-~]").substring(0,index):this.rng("[\x00-\xff]").substring(256-index,256);
if(typeof(this.symbols[index])=="function") this.symbols[index] = this.symbols[index](); // process references
if(typeof(this.symbols[index])=="object") this.symbols[index] = this.rng(this.symbols[index][0]); // process range_replace
return this.symbols[index];
}
this.rng = function(_s) {
var _a = _s.match(/\[.-.\]/); if(_a==null) return _s; else { _a=[_a[0].charCodeAt(1),_a[0].charCodeAt(3)];
return this.rng(_s.replace(RegExp("\\[(\\x"+("0"+_a[0].toString(16)).slice(-2)+"-\\x"+_a[1].toString(16)+")\\]","g")
,String.fromCharCode(..." ".repeat(_a[1]-_a[0]+1).split("").map((_e,_i)=>_i+_a[0])) )) }
}
this.selftest = function() {
var _a={}; for(var _o in this.symbols) _a[_o] = this.getsymbols(_o).length; // built-in symbols
for(_o=2;_o<=95;_o++) _a[_o] = this.getsymbols(_o).length; _a[256]=256; // symbol range 2-95 + 256 (96-255 is similar)
var _s = "",_a = Object.keys(_a).sort(function(a,b){return _a[a]-_a[b]}); // sort merged list
for(var _i in _a) { // iterate number systems
_o = {fromBase:10, toBASE:_a[_i]}; var _r = this.convert("",10,_o.toBASE)
_s += "\r\n\oBASE.convert(n, '"+_o.fromBase+"', '"+_o.toBASE+"') ["+this.fromSymbols+"] ["+this.toSymbols+"]\r\n"
for(var _n=0;_n<(this.fromSymbols.length+2);_n++) { // iterate numbers
_r = this.convert(String(_n),_o.fromBase,_o.toBASE)
_s += _n+(String(_n)==this.convert(_r,_o.toBASE,_o.fromBase)?">":"?")+"["+_r+"] ";
}
}
return _s
}
var add = function(x, y, base) {
var _m = Math.max(x.length, y.length);
for(var _c = _n = 0,_r = []; _n < _m || _c; _c = Math.floor(_z / base)) {
var _z = _c + (_n < x.length ? x[_n] : 0) + (_n < y.length ? y[_n] : 0);
var _n = _r.push(_z % base);
}
return _r;
}
var mul = function(x, pow, base) {
for(var _r = x < 0 ? null : []; x > 0; x = x >> 1) {
if(x & 1) _r = add(_r, pow, base);
pow = add(pow, pow, base);
}
return _r;
}
}
Usage:
// quick test, convert from base45 to base32, using custom symbols for base85 and back to base45
var oBASE = new BASE();
var n = "THIS IS A NUMBER"; // Base 45 code = 'qr-alnum'
console.log(n); // Result: 'THIS IS A NUMBER'
var n = oBASE.convert(n,"qr-alnum",32); // Base 45 to Base 32 = 'base32hex'
console.log(n); // Result: '4ONI84LCTLJ1U08G1N'
var s85 = oBASE.rng("[0-9][a-z][A-Z].-:+=^!/*?&<>()[]{}#%$#"); // 32/Z85 custom symbols
var n = oBASE.convert(n,"base32hex",[s85]); // 'base2hex' to custom Base 85
console.log(n); // Result: 'fnaxrZP)?5d[DG'
var n = oBASE.convert(n,[s85],45); // Custom Base 85 to Base 45 = 'qr-alnum'
console.log(n); // Result: 'THIS IS A NUMBER'
function BASE(){this.convert=function(o,r,n){this.fromSymbols="object"==typeof r?r[0]:this.getsymbols(r),this.toSymbols="object"==typeof n?n[0]:this.getsymbols(n),r=this.fromSymbols.length,n=this.toSymbols.length;var i=[0];for(o=o.split("");o.length>0&&i[i.push(this.fromSymbols.indexOf(o.pop()))-1]>=0;);var h=i.shift()+i[i.length-1]>=0?i:null;if(null===h)return null;for(var e=0,l=(i=[],[1]);e<h.length;e++)i=t(i,s(h[e],l,n),n),l=s(r,l,n);e=i.length-1;for(var m="";e>=0;m+=this.toSymbols[i[e--]]);return 0==m.length?this.toSymbols[0]:m},this.symbols={32:function(){return this.base32hex},36:["[0-9][A-Z]"],45:function(){return this["qr-alnum"]},58:function(){return this.Bitcoin},64:["[A-Z][a-z][0-9]+/"],85:function(){return this["RFC 1924"]},91:['[A-Z][a-z][0-9]!#$%&()*+,./:;<=>?#[]^_`{|}~"'],94:["[!-~]"],geohash:["[0-9][b-h]jkmn[p-z]"],"RFC 4648":["[A-Z][2-7]"],base32hex:["[0-9][A-V]"],"qr-alnum":["[0-9][A-Z] $%*+-./:"],Bitcoin:["[1-9][A-H]JKLMN[P-Z][a-k][m-z]"],"RFC 1924":["[0-9][A-Z][a-z]!#$%&()*+-;<=>?#^_`{|}~"]},this.getsymbols=function(t){return void 0===this.symbols[t]&&(this.symbols[t]=t<95?this.rng(t<64?"[0-9][A-Z][a-z]+":"[A-Z][a-z][0-9][!-/][:-#][[-`][{-~]").substring(0,t):this.rng("[\0-ÿ]").substring(256-t,256)),"function"==typeof this.symbols[t]&&(this.symbols[t]=this.symbols[t]()),"object"==typeof this.symbols[t]&&(this.symbols[t]=this.rng(this.symbols[t][0])),this.symbols[t]},this.rng=function(t){var s=t.match(/\[.-.\]/);return null==s?t:(s=[s[0].charCodeAt(1),s[0].charCodeAt(3)],this.rng(t.replace(RegExp("\\[(\\x"+("0"+s[0].toString(16)).slice(-2)+"-\\x"+s[1].toString(16)+")\\]","g"),String.fromCharCode(..." ".repeat(s[1]-s[0]+1).split("").map((t,o)=>o+s[0])))))},this.selftest=function(){var t={};for(var s in this.symbols)t[s]=this.getsymbols(s).length;for(s=2;s<=95;s++)t[s]=this.getsymbols(s).length;t[256]=256;var o="";t=Object.keys(t).sort(function(s,o){return t[s]-t[o]});for(var r in t){s={fromBase:10,toBASE:t[r]};var n=this.convert("",10,s.toBASE);o+="\r\noBASE.convert(n, '"+s.fromBase+"', '"+s.toBASE+"') ["+this.fromSymbols+"] ["+this.toSymbols+"]\r\n";for(var i=0;i<this.fromSymbols.length+2;i++)n=this.convert(String(i),s.fromBase,s.toBASE),o+=i+(String(i)==this.convert(n,s.toBASE,s.fromBase)?">":"?")+"["+n+"] "}return o};var t=function(t,s,o){for(var r=Math.max(t.length,s.length),n=e=0,i=[];e<r||n;n=Math.floor(h/o))var h=n+(e<t.length?t[e]:0)+(e<s.length?s[e]:0),e=i.push(h%o);return i},s=function(s,o,r){for(var n=s<0?null:[];s>0;s>>=1)1&s&&(n=t(n,o,r)),o=t(o,o,r);return n}}
Self-Test:
// quick test, convert from base45 to base32, using custom symbols for base85 and back to base45
var oBASE = new BASE();
console.log(oBASE.selftest())
function BASE(){this.convert=function(o,r,n){this.fromSymbols="object"==typeof r?r[0]:this.getsymbols(r),this.toSymbols="object"==typeof n?n[0]:this.getsymbols(n),r=this.fromSymbols.length,n=this.toSymbols.length;var i=[0];for(o=o.split("");o.length>0&&i[i.push(this.fromSymbols.indexOf(o.pop()))-1]>=0;);var h=i.shift()+i[i.length-1]>=0?i:null;if(null===h)return null;for(var e=0,l=(i=[],[1]);e<h.length;e++)i=t(i,s(h[e],l,n),n),l=s(r,l,n);e=i.length-1;for(var m="";e>=0;m+=this.toSymbols[i[e--]]);return 0==m.length?this.toSymbols[0]:m},this.symbols={32:function(){return this.base32hex},36:["[0-9][A-Z]"],45:function(){return this["qr-alnum"]},58:function(){return this.Bitcoin},64:["[A-Z][a-z][0-9]+/"],85:function(){return this["RFC 1924"]},91:['[A-Z][a-z][0-9]!#$%&()*+,./:;<=>?#[]^_`{|}~"'],94:["[!-~]"],geohash:["[0-9][b-h]jkmn[p-z]"],"RFC 4648":["[A-Z][2-7]"],base32hex:["[0-9][A-V]"],"qr-alnum":["[0-9][A-Z] $%*+-./:"],Bitcoin:["[1-9][A-H]JKLMN[P-Z][a-k][m-z]"],"RFC 1924":["[0-9][A-Z][a-z]!#$%&()*+-;<=>?#^_`{|}~"]},this.getsymbols=function(t){return void 0===this.symbols[t]&&(this.symbols[t]=t<95?this.rng(t<64?"[0-9][A-Z][a-z]+":"[A-Z][a-z][0-9][!-/][:-#][[-`][{-~]").substring(0,t):this.rng("[\0-ÿ]").substring(256-t,256)),"function"==typeof this.symbols[t]&&(this.symbols[t]=this.symbols[t]()),"object"==typeof this.symbols[t]&&(this.symbols[t]=this.rng(this.symbols[t][0])),this.symbols[t]},this.rng=function(t){var s=t.match(/\[.-.\]/);return null==s?t:(s=[s[0].charCodeAt(1),s[0].charCodeAt(3)],this.rng(t.replace(RegExp("\\[(\\x"+("0"+s[0].toString(16)).slice(-2)+"-\\x"+s[1].toString(16)+")\\]","g"),String.fromCharCode(..." ".repeat(s[1]-s[0]+1).split("").map((t,o)=>o+s[0])))))},this.selftest=function(){var t={};for(var s in this.symbols)t[s]=this.getsymbols(s).length;for(s=2;s<=95;s++)t[s]=this.getsymbols(s).length;t[256]=256;var o="";t=Object.keys(t).sort(function(s,o){return t[s]-t[o]});for(var r in t){s={fromBase:10,toBASE:t[r]};var n=this.convert("",10,s.toBASE);o+="\r\noBASE.convert(n, '"+s.fromBase+"', '"+s.toBASE+"') ["+this.fromSymbols+"] ["+this.toSymbols+"]\r\n";for(var i=0;i<this.fromSymbols.length+2;i++)n=this.convert(String(i),s.fromBase,s.toBASE),o+=i+(String(i)==this.convert(n,s.toBASE,s.fromBase)?">":"?")+"["+n+"] "}return o};var t=function(t,s,o){for(var r=Math.max(t.length,s.length),n=e=0,i=[];e<r||n;n=Math.floor(h/o))var h=n+(e<t.length?t[e]:0)+(e<s.length?s[e]:0),e=i.push(h%o);return i},s=function(s,o,r){for(var n=s<0?null:[];s>0;s>>=1)1&s&&(n=t(n,o,r)),o=t(o,o,r);return n}}
to convert numbers into different bases in JavaScript or typescript using the following ways.
function binary(number) {
console.log((number >>> 0).toString(2)); //base 2 for binary
}
binary(-7);
function octal(number) {
console.log(number.toString(8)); //base 8 for octal
}
octal(15);
function hex(number) {
console.log(number.toString(16)); //base 16 for hex
}
hex(15);
here in the binary function, you can use number.toString(2) function, but the problem occurs when representing negative numbers. so that you can use the unsigned right shift bitwise operator (>>>) to fix this issue.
I am writing this answer simply because I was kinda stupid to understand the difference between parseInt and .toString().
Here is the difference
parseInt
parseInt(str, base) will convert the str to an Integer and base here is used to tell parseInt which base the str is in. I thought the base here was what the str would get converted to. But thats not true. parseInt is just used to convert a number in any base to an integer in base10.
.toString()
number.toString(base) is used to convert the number into a number with base base and it assumes that number is in Integer form. So if the number is in hex format and you want to convert it to binary you need to convert the number first to Integer using parseInt and then you can use this function to change the base.
Hope this helps if you are as stupid as me. :)
You can also convert number in hexadecimal to decimal as follows:
var a="8F";
var b=a.split("");
var result=0;var hex_multiplier=1;
for(var i=0;i<b.length;i++){
result +=parseInt(b[i],16)*hex_multiplier;
hex_multiplier *=16;
}
console.log(result);
where you can change a with any hexadecimal number and get the result in decimal form.
You can use JavaScript's built-in integer literals for some scenarios:
function binaryToDecimal(binaryString) {
return Number('0b' + binaryString.replace('-', '')) * signOf(binaryString);;
}
function octalToDecimal(octalString) {
return Number('0o' + octalString.replace('-', '')) * signOf(octalString);
}
function hexToDecimal(hexString) {
return Number('0x' + hexString.replace('-', '')) * signOf(hexString);
}
function signOf(n) {
return n.trim()[0] == '-' ? -1 : 1;
}
console.log(binaryToDecimal('-0101'),
octalToDecimal('-052171'),
hexToDecimal('deadbeef'));
This code converts a number to an arbitrary-large base, outputting an array of digits.
function convertBase(num, base) {
var result = [];
while(num >= 1) {
result.unshift(num % base);
num = Math.floor(num / base);
}
return result;
}
console.log(convertBase(100, 12)); // [8, 4]
console.log(convertBase(5114, 64)); // [1, 15, 58]
TypeScript Implementation that supports decimal and int:
class Digit {
private readonly digitMap: Map<string, number>;
constructor(readonly digits: string, readonly maxDigits = 10) {
this.digitMap = new Map<string, number>();
for (let i = 0; i < digits.length; i += 1) {
if (digits[i] === ".") {
throw new TypeError(`Digits should not contain the "." mark.`);
}
if (this.digitMap.has(digits[i])) {
throw new TypeError(`Duplicated digit character.`);
}
this.digitMap.set(digits[i], i);
}
}
to = (x: number) => {
const int = Math.floor(x);
const dec = x - int;
let intRemains = int;
let intResult = "";
while (true) {
intResult = this.digits[intRemains % this.digits.length] + intResult;
intRemains = Math.floor(intRemains / this.digits.length);
if (intRemains === 0) break;
}
if (dec > 0) {
let decRemains = dec;
let decResult = "";
for (let i = 0; i < this.maxDigits; i += 1) {
const stepCache = decRemains * this.digits.length;
const decInt = Math.floor(stepCache);
decResult = decResult + this.digits[decInt];
decRemains = stepCache - decInt;
if (decRemains === 0) break;
}
if (decResult === "0") return intResult;
return intResult + "." + decResult;
}
return intResult;
};
from = (x: string) => {
const splitted = x.split(".");
if (splitted.length > 2) return Number.NaN;
const [int, dec] = splitted;
let result = 0;
for (let i = 0; i < int.length; i += 1) {
const digit = int[int.length - i - 1];
const oct = this.digitMap.get(digit);
if (oct === undefined) return Number.NaN;
result += oct * Math.pow(this.digits.length, i);
}
if (dec) {
for (let i = 0; i < dec.length; i += 1) {
const digit = dec[i];
const oct = this.digitMap.get(digit);
if (oct === undefined) return Number.NaN;
result += oct * Math.pow(this.digits.length, 0 - i - 1);
}
}
return result;
};
}
Here're the example about how to use it:
Creating the converter:
const d = new Digit("0123456789");
Convert a number to string:
d.to(1.2345);
Convert a string to number:
d.from("1.2345");
You can also set the second parameter to control the maximum number of decimal places, for example:
const d0 = new Digit("abcdABCD", 10);
d0.to(0.96);
// a.DBdAbcbDcD
const d1 = new Digit("abcdABCD", 20);
d1.to(0.96);
// a.DBdAbcbDcDacAdCBC
Monkey patched Number prototype for all radixes up to and including 64
( inspired by and derived from #nirvana's answer )
NumberToStringPatched.__patched = NumberToStringPatched;
if (Number.prototype.toString.__patched!==NumberToStringPatched) {
NumberToStringPatched.__unpatched = Number.prototype.toString;
Number.prototype.toString = NumberToStringPatched;
}
NumberParseIntPatched.__patched = NumberParseIntPatched;
if (Number.parseInt.__patched!==NumberParseIntPatched) {
NumberParseIntPatched.__unpatched = Number.parseInt;
Number.parseInt = NumberParseIntPatched;
}
function NumberToStringPatched(base=10) {
if (base<33||base>64) return NumberToStringPatched.__unpatched.call(this,base);
return convertToBase(this,base);
}
function NumberParseIntPatched(str,base=10) {
if (base<33||base>64) return NumberParseIntPatched.__unpatched.call(this,str,base);
return convertFromBase(str,base);
}
const numberCharSet=(()=>{
let chars = "0123456789";
for (let c='a';c<='z';c=String.fromCharCode(c.charCodeAt(0)+1)) {
chars+=c;
}
for (let c='A';c<='Z';c=String.fromCharCode(c.charCodeAt(0)+1)) {
chars+=c;
}
return (chars+'_$').split('');
})();
function convertToBase(num, base) {
var result = '';
while(num >= 1) {
result = numberCharSet[num % base]+result;
num = Math.floor(num / base);
}
return result;
}
function convertFromBase(str, base) {
let charset = numberCharSet.slice(0,base);
if (typeof str==='number') str=str.toString(base);
if (base <= 26) str=str.toLowerCase();
let digits = str.split('').map(function(c){
let x = charset.indexOf(c);
if (x<0) throw new Error("invalid digit for given radix "+base+': '+c);
return x;
});
let result = digits.shift();
while (digits.length) {
result=(result*base)+digits.shift();
}
return result;
}
for (let i = 0;i<64;i++) {
console.log(i.toString(64));
}
console.log(9000);
console.log(9 * 10 * 10 * 10);
console.log(0xf000);
console.log(15 * 16 * 16 * 16);
console.log(Number.parseInt('$000',64));
console.log(63 * 64 * 64 * 64);
Your Own recursion method for creating base2 conversions.
As mentioned by the users above
let n = 13; console.log(n.toString(2)); will result in 13 conversion from base 10 to base 2.
But in case if you want to program the same. I have written a recursive method to do the same. which just simply divide by 2 and then count remainders.
// #author Tarandeep Singh :: Created recursive converter from base 10 to base 2
// #date : 2017-04-11
// Convert Base 10 to Base 2, We should reverse the output
// For Example base10to2(10) = "0101" just do res = base10to2(10).split('').reverse().join();
function base10to2(val, res = '') {
if (val >= 2) {
res += '' + val % 2;
return base10to2(val = Math.floor(val / 2), res);
} else {
res += '' + 1
return res;
}
}
let n = 13;
var result = base10to2(n).split('').reverse().join();
document.write(`Converting ${n} into Base2 is ${result}`);