Here's the question:
A Narcissistic Number is a positive number which is the sum of its own digits, each raised to the power of the number of digits in a given base. In this Kata, we will restrict ourselves to decimal (base 10).
For example, take 153 (3 digits), which is narcisstic:
1^3 + 5^3 + 3^3 = 1 + 125 + 27 = 153
Your code must return true or false (not 'true' and 'false') depending upon whether the given number is a Narcissistic number in base 10.
My Code is:
function narcissistic(value) {
let vLen = value.length;
let sum = 0;
for (let i = 0; i < vLen; i++) {
sum += Math.pow(value[i], vLen);
}
if (sum == value) {
return true;
} else {
return false;
}
}
But I'm getting errors. What should I do?
Numbers don't have .length, convert to string first
vLen[i], you cant treat a number as array, again, convert to string to use that syntax.
The return can be simplefied to return (sum === value);
function narcissistic(value) {
let sVal = value.toString();
let vLen = sVal.length;
let sum = 0;
for (let i = 0; i < vLen; i++) {
sum += Math.pow(sVal[i], vLen);
}
return (sum === value);
}
console.log(narcissistic(153));
console.log(narcissistic(111));
Well... There are several things wrong with this code, but I think there is mostly a problem with the types of your input.
I'll show you how you can cast the types of your input to make sure you work with the types you need:
Also... You should try to avoid using the == operator and try to use === instead (same goes for != and !==), because the == and != don't try to match the types, resulting in sometimes unpredictable results
function narcissistic(value) {
valueStr = String(value);
let vLen = valueStr.length;
let sum = 0;
for (let i = 0; i < vLen; i++) {
sum += Number(valueStr[i]) ** vLen;
}
if (sum === value) {
return true;
} else {
return false;
}
}
if(narcissistic(153)) {
console.log("narcissistic(153) is true!") // expected value: true
}
All the first 9 digits from 1 to 9 is Narcissistic number as there length is 1 and there addition is always same.
So, first we are checking weather the number is greater than 9 or not.
if(num>9) =>false than it's a narcissistic number.
-if(num>9) =>true than we have to split number into digits for that I have used x = num.toString().split('');. Which is first converting number to String and than using split() function to split it.
Than , we are looping through each digit and digitsSum += Math.pow(Number(digit), x.length); adding the power of digit to const isNarcissistic = (num) => { let x = 0; let digitsSum.
at the end, we are comparing both num & digitsSum if there are matched than number is narcissistic else not.
const isNarcissistic = (num) => {
let x = 0;
let digitsSum = 0;
if (num > 9) {
x = num.toString().split('');
x.forEach(digit => {
digitsSum += Math.pow(Number(digit), x.length);
});
if (digitsSum == num) {
return true;
} else {
return false;
}
} else {
return true;
}
}
console.log(isNarcissistic(153));
console.log(isNarcissistic(1634));
console.log(isNarcissistic(1433));
console.log(isNarcissistic(342));
I am completely new to Javascript and trying to solve a simple problem now for more than two weeks and still not getting it(please help).
TASK ::::
Read a 4 digit Number e.g. 5678
Write a function
Split/separate the numbers and than build (5678, 567, 56, 5), than check if the numbers(5678, 567, 56, 5) are Prime numbers.
Give in Console/Result if 5678 a prime number or not, 567 a prime number or not and so on.
Check "if all numbers are Prime" than show result "All prime" if not show result "Not all prime".
Trying to solve the problem with (if else) but not really getting it, because i know very less about Javascript (arrays, string, split, slice) yet.
please help me understand. Thanks.
var a = 123456789;
var b = a.toString().length; //<<--->> ANTWORT: 9
document.write('ANTWORT: ',a );
for (i=0; i<b; i++) {
var x = a.toString().slice(0, -i);
document.write(x, ",");
}
function isPrime{
for(var i = 2; i < a; i++);
if(num % i === 0) return false;
return num > 1;
}
//integer is a string at the moment
integer = prompt("Enter a integer: ");
//initialize array for dictionary
dictArray = [];
stuff = document.getElementById("stuff");
//loop through all values of the string
for (var i = integer.length; i > 0; i--)
{
//take a substring from 0 to the ith char and turn it into an int
num = parseInt(integer.substring(0, i));
//add a dictionary to the array the tells what the number is
//and if it was prime or not as a bool
dictArray.push({"num": num, "prime": isprime(num)});
(dictArray[integer.length - i]["prime"]) ? stuff.innerHTML += "<br>" + num + " is prime." : stuff.innerHTML += "<br>" + num + " is not prime.";
}
function isprime(num)
{
if (num <= 3) return num >= 1;
if ((num % 2 === 0) || (num % 3 === 0)) return false;
let count = 5;
while (Math.pow(count, 2) <= num) {
if (num % count === 0 || num % (count + 2) === 0) return false;
count += 6;
}
return true;
}
//print the array
(dictArray.find(x => !x.prime) == undefined) ? stuff.innerHTML += "<br>All prime!" : stuff.innerHTML += "<br>Not all prime!";
//console.log(dictArray);
<div id="stuff">
</div>
Following are the rules:
Generate random numbers of length N.
Not more than two consecutive digits in a number should be the same.
I written code, but even though 2 same consecutive digits in a number are allowed, it's not working. All unique random numbers are generated.
I keep one temporary variable, which stores the previous number generated, if it matches the present generate number, then discard and generate again.
while (rnum.length<=7)
{
gennum = randomNumericChar();
if(rnum.length==0) {
rnum = rnum.concat(gennum);
prevnum = gennum;
} else if(gennum!=prevnum) {
rnum = rnum.concat(gennum);
prevnum = gennum;
}
}
return rnum;
FOund solution:
Hi, i got the solution. ` var rnum = "" ;
var random;
while(rnum.length<=7)
{
random= generaterandom();
if(rnum.length<2)
{
rnum = rnum.concat(random);
}else
{
//check whether previous two numbers are same, if not then append generated random number
if(!(random==rnum.charAt(rnum.length-1) && random==rnum.charAt(rnum.length-2)))
{
rnum = rnum.concat(random);
}
}
}`
This might be your solution:
function randomNumericChar(lastNumber) {
var num = Math.floor((Math.random() * 10) + 1);
if (lastNumber !== null && num === lastNumber) {
return randomNumericChar(lastNumber);
} else {
return num;
}
}
function createNumber(n) {
var randomNumber = '';
var lastChar = null;
while (randomNumber.length < n) {
var num = randomNumericChar(lastChar);
if (((randomNumber.length + 1) % 2) === 1) {
lastChar = num;
}
randomNumber += num;
}
return randomNumber;
}
var randomNumber = createNumber(10);
Edit: forgot about the fact that there might be 1 consecutive number.
I'm using Angular "currency" filter to show price in a shopping cart. The prices are fetched from a back end server. So sometimes the price may not be available to show to the user. In that case I just want to show the user that the price is not available in the same field as of currency field. I can not show plain text in a currency filter. The only solution I found is to keep another text field to show/hide when a price is not available.But this is some what unnecessary I think. Is there any way to extend or override the built in "currency" filter of Angular js ?. Kindly appreciate some help.
<div class="large-12 medium-12 small-12 columns pad-none nzs-pro-list-item-price">
{{item.ItmPrice|currency}}
</div>
Create your custom filter which will internally use currency when value is present, otherwise it will return text which you want to show instead.
Markup
{{amount | customFormat:"USD$": "N/A"}}
Filter
.filter('customFormat', function($filter) {
return function(value, format, text) {
if (angular.isDefined(value) && value != null)
return $filter('currency')(value, format);
else
return text;
}
});
Working Plunkr
I feel the best way is to rewrite currency filter, so that you have fill control over Pattern, Grouping Separator, Decimal Separator & symbol position
<span>
{{26666662.5226 | fmtCurrency :"##.###,###" : "." : "," : "$" : "first"}}
</span>
Resluts in: $26.666.662,523
Filter:
app.filter("fmtCurrency", ['CurrencyService', function sasCurrency(CurrencyService) {
return function (amount, pattern, groupingSeparator, decimalSeparator, currencySymbol, symbolPosition) {
var patternInfo = CurrencyService.parsePattern(pattern, groupingSeparator, decimalSeparator);
var formattedCurrency = CurrencyService.formatCurrency(amount, patternInfo, groupingSeparator, decimalSeparator);
if (symbolPosition === 'last')
return formattedCurrency + currencySymbol;
else
return currencySymbol + formattedCurrency;
};
}])
Service: formatNumber which is the same function used in angular currency filter is being used here inside service
app.service("CurrencyService", function () {
var PATTERN_SEP = ';',
DECIMAL_SEP = '.',
GROUP_SEP = ',',
ZERO = '0',
DIGIT = "#";
var MAX_DIGITS = 22;
var ZERO_CHAR = '0';
return {
parsePattern: function (pattern, groupingSeparator, decimalSeparator) {
return parsePattern(pattern, groupingSeparator, decimalSeparator);
},
formatCurrency: function (amount, patternInfo, groupingSeparator, decimalSeparator) {
return formatNumber(amount, patternInfo, groupingSeparator, decimalSeparator);
}
}
/*
* Currency formatter utility
*/
function isUndefined(value) { return typeof value === 'undefined'; }
/**
* main function for parser
* #param str {string} pattern to be parsed (e.g. #,##0.###).
*/
function parsePattern(pattern, groupSep, decimalSep) {
DECIMAL_SEP = decimalSep;
GROUP_SEP = groupSep;
var p = {
minInt: 1,
minFrac: 0,
maxFrac: 0,
posPre: '',
posSuf: '',
negPre: '',
negSuf: '',
gSize: 0,
lgSize: 0
};
var ZERO = '0',
DIGIT = "#";
var parts = pattern.split(PATTERN_SEP),
positive = parts[0],
negative = parts[1];
var parts = positive.split(DECIMAL_SEP),
integer = parts[0],
fraction = parts[1];
console.log(parts);
p.posPre = integer.substr(0, integer.indexOf(DIGIT));
if (fraction) {
for (var i = 0; i < fraction.length; i++) {
var ch = fraction.charAt(i);
console.log(ch, ZERO, DIGIT);
if (ch == ZERO)
p.minFrac = p.maxFrac = i + 1;
else if (ch == DIGIT)
p.maxFrac = i + 1;
else
p.posSuf += ch;
}
}
var groups = integer.split(GROUP_SEP);
p.gSize = groups[1] ? groups[1].length : 0;
p.lgSize = (groups[2] || groups[1]) ? (groups[2] || groups[1]).length : 0;
if (negative) {
var trunkLen = positive.length - p.posPre.length - p.posSuf.length,
pos = negative.indexOf(DIGIT);
p.negPre = negative.substr(0, pos).replace(/\'/g, '');
p.negSuf = negative.substr(pos + trunkLen).replace(/\'/g, '');
} else {
// hardcoded '-' sign is fine as all locale use '-' as MINUS_SIGN. (\u2212 is the same as '-')
p.negPre = '-' + p.posPre;
p.negSuf = p.posSuf;
}
return p;
}
function isString(value) { return typeof value === 'string'; }
function isNumber(value) { return typeof value === 'number'; }
/**
* Format a number into a string
* #param {number} number The number to format
* #param {{
* minFrac, // the minimum number of digits required in the fraction part of the number
* maxFrac, // the maximum number of digits required in the fraction part of the number
* gSize, // number of digits in each group of separated digits
* lgSize, // number of digits in the last group of digits before the decimal separator
* negPre, // the string to go in front of a negative number (e.g. `-` or `(`))
* posPre, // the string to go in front of a positive number
* negSuf, // the string to go after a negative number (e.g. `)`)
* posSuf // the string to go after a positive number
* }} pattern
* #param {string} groupSep The string to separate groups of number (e.g. `,`)
* #param {string} decimalSep The string to act as the decimal separator (e.g. `.`)
* #param {[type]} fractionSize The size of the fractional part of the number
* #return {string} The number formatted as a string
*/
function formatNumber(number, pattern, groupSep, decimalSep, fractionSize) {
if (!(isString(number) || isNumber(number)) || isNaN(number)) return '';
var isInfinity = !isFinite(number);
var isZero = false;
var numStr = Math.abs(number) + '',
formattedText = '',
parsedNumber;
if (isInfinity) {
formattedText = '\u221e';
} else {
parsedNumber = parse(numStr, '.');
roundNumber(parsedNumber, fractionSize, pattern.minFrac, pattern.maxFrac);
var digits = parsedNumber.d;
var integerLen = parsedNumber.i;
var exponent = parsedNumber.e;
var decimals = [];
isZero = digits.reduce(function (isZero, d) { return isZero && !d; }, true);
// pad zeros for small numbers
while (integerLen < 0) {
digits.unshift(0);
integerLen++;
}
// extract decimals digits
if (integerLen > 0) {
decimals = digits.splice(integerLen, digits.length);
} else {
decimals = digits;
digits = [0];
}
// format the integer digits with grouping separators
var groups = [];
if (digits.length >= pattern.lgSize) {
groups.unshift(digits.splice(-pattern.lgSize, digits.length).join(''));
}
while (digits.length > pattern.gSize) {
groups.unshift(digits.splice(-pattern.gSize, digits.length).join(''));
}
if (digits.length) {
groups.unshift(digits.join(''));
}
formattedText = groups.join(groupSep);
// append the decimal digits
if (decimals.length) {
formattedText += decimalSep + decimals.join('');
}
if (exponent) {
formattedText += 'e+' + exponent;
}
}
if (number < 0 && !isZero) {
return pattern.negPre + formattedText + pattern.negSuf;
} else {
return pattern.posPre + formattedText + pattern.posSuf;
}
}
function parse(numStr, decimalSep) {
var exponent = 0, digits, numberOfIntegerDigits;
var i, j, zeros;
DECIMAL_SEP = decimalSep;
// Decimal point?
if ((numberOfIntegerDigits = numStr.indexOf(DECIMAL_SEP)) > -1) {
numStr = numStr.replace(DECIMAL_SEP, '');
}
// Exponential form?
if ((i = numStr.search(/e/i)) > 0) {
// Work out the exponent.
if (numberOfIntegerDigits < 0) numberOfIntegerDigits = i;
numberOfIntegerDigits += +numStr.slice(i + 1);
numStr = numStr.substring(0, i);
} else if (numberOfIntegerDigits < 0) {
// There was no decimal point or exponent so it is an integer.
numberOfIntegerDigits = numStr.length;
}
// Count the number of leading zeros.
for (i = 0; numStr.charAt(i) === ZERO_CHAR; i++) {/* jshint noempty: false */ }
if (i === (zeros = numStr.length)) {
// The digits are all zero.
digits = [0];
numberOfIntegerDigits = 1;
} else {
// Count the number of trailing zeros
zeros--;
while (numStr.charAt(zeros) === ZERO_CHAR) zeros--;
// Trailing zeros are insignificant so ignore them
numberOfIntegerDigits -= i;
digits = [];
// Convert string to array of digits without leading/trailing zeros.
for (j = 0; i <= zeros; i++ , j++) {
digits[j] = +numStr.charAt(i);
}
}
// If the number overflows the maximum allowed digits then use an exponent.
if (numberOfIntegerDigits > MAX_DIGITS) {
digits = digits.splice(0, MAX_DIGITS - 1);
exponent = numberOfIntegerDigits - 1;
numberOfIntegerDigits = 1;
}
return { d: digits, e: exponent, i: numberOfIntegerDigits };
}
/**
* Round the parsed number to the specified number of decimal places
* This function changed the parsedNumber in-place
*/
function roundNumber(parsedNumber, fractionSize, minFrac, maxFrac) {
var digits = parsedNumber.d;
var fractionLen = digits.length - parsedNumber.i;
// determine fractionSize if it is not specified; `+fractionSize` converts it to a number
fractionSize = (isUndefined(fractionSize)) ? Math.min(Math.max(minFrac, fractionLen), maxFrac) : +fractionSize;
// The index of the digit to where rounding is to occur
var roundAt = fractionSize + parsedNumber.i;
var digit = digits[roundAt];
if (roundAt > 0) {
// Drop fractional digits beyond `roundAt`
digits.splice(Math.max(parsedNumber.i, roundAt));
// Set non-fractional digits beyond `roundAt` to 0
for (var j = roundAt; j < digits.length; j++) {
digits[j] = 0;
}
} else {
// We rounded to zero so reset the parsedNumber
fractionLen = Math.max(0, fractionLen);
parsedNumber.i = 1;
digits.length = Math.max(1, roundAt = fractionSize + 1);
digits[0] = 0;
for (var i = 1; i < roundAt; i++) digits[i] = 0;
}
if (digit >= 5) {
if (roundAt - 1 < 0) {
for (var k = 0; k > roundAt; k--) {
digits.unshift(0);
parsedNumber.i++;
}
digits.unshift(1);
parsedNumber.i++;
} else {
digits[roundAt - 1]++;
}
}
// Pad out with zeros to get the required fraction length
for (; fractionLen < Math.max(0, fractionSize); fractionLen++) digits.push(0);
// Do any carrying, e.g. a digit was rounded up to 10
var carry = digits.reduceRight(function (carry, d, i, digits) {
d = d + carry;
digits[i] = d % 10;
return Math.floor(d / 10);
}, 0);
if (carry) {
digits.unshift(carry);
parsedNumber.i++;
}
}
})
$provide.decorator('currencyFilter', ['$delegate',
function ($delegate) {
var crncyFilter = $delegate;
var extendsFilter = function () {
var res = crncyFilter.apply(this, arguments);
if (arguments[2]) {
var digi1 = arguments[2] || 2;
return arguments[1] + Number(arguments[0]).toFixed(digi1);
}
else {
if (arguments[1] == "¥") {
return arguments[1] + Number(arguments[0]).toFixed(1);
}
}
};
return extendsFilter;
}]);
This is the way to Override Decimal digit
How to format numbers in JavaScript?
JavaScript culture sensitive currency formatting
The best you have with JavaScript is toFixed() and toPrecision() functions on your numbers.
var num = 10;
var result = num.toFixed(2); // result will equal 10.00
num = 930.9805;
result = num.toFixed(3); // result will equal 930.981
num = 500.2349;
result = num.toPrecision(4); // result will equal 500.2
num = 5000.2349;
result = num.toPrecision(4); // result will equal 5000
num = 555.55;
result = num.toPrecision(2); // result will equal 5.6e+2
Currency, commas, and other formats will have to be either done by you or a third party library.
The improved script (the previous was buggy, sorry; to be honest I haven't tested this exaustively either), it works like php number_format:
function formatFloat(num,casasDec,sepDecimal,sepMilhar) {
if (num < 0)
{
num = -num;
sinal = -1;
} else
sinal = 1;
var resposta = "";
var part = "";
if (num != Math.floor(num)) // decimal values present
{
part = Math.round((num-Math.floor(num))*Math.pow(10,casasDec)).toString(); // transforms decimal part into integer (rounded)
while (part.length < casasDec)
part = '0'+part;
if (casasDec > 0)
{
resposta = sepDecimal+part;
num = Math.floor(num);
} else
num = Math.round(num);
} // end of decimal part
while (num > 0) // integer part
{
part = (num - Math.floor(num/1000)*1000).toString(); // part = three less significant digits
num = Math.floor(num/1000);
if (num > 0)
while (part.length < 3) // 123.023.123 if sepMilhar = '.'
part = '0'+part; // 023
resposta = part+resposta;
if (num > 0)
resposta = sepMilhar+resposta;
}
if (sinal < 0)
resposta = '-'+resposta;
return resposta;
}