Remove numbers that aren't within square brackets in JS - javascript

I have a generated a series of arrays in JavaScript but need to remove all numbers that are outside of square brackets.
Now I'm aware I need to use some form of Regex but I'm not sure how to use it in this instance.
Here's a sample of my arrays:
1[1,0.031410759078128],2[2,0.062790519529313],3[3,0.094108313318514],4[4,0.1253332335643],5[5,0.15643446504023]
etc.
How can I remove all the numbers that aren't in square brackets?

You will want to use a zero-width lookahead assertion. The Regex string below will select all numbers in sequence that come directly before a '['.
/([0-9]+)(?=\[)+/g
Rexexr.com is a great resource. http://regexr.com/3e63k

var stripNumsOutside = function(s) {
var result = "";
var insideBrackets = false;
var curChar;
for (var i = 0;
(i < s.length); i++) {
curChar = s[i];
if (curChar == "[") {
insideBrackets = true;
}
if ((insideBrackets) || (curChar == ",")) {
result += curChar;
};
if (curChar == "]") {
insideBrackets = false;
};
}
return result;
}
console.log(stripNumsOutside("1[1,0.031410759078128],2[2,0.062790519529313],3[3,0.094108313318514],4[4,0.1253332335643],5[5,0.15643446504023]"));

Related

How to alternate the case of a string

I'm working on alternating the case of a string (for example asdfghjkl to AsDfGhJkL).
I tried to do this. I found some code that is supposed to do it, but it doesn't seem to be working.
var str="";
var txt=document.getElementById('input').value;
for (var i=0; i<txt.length; i+2){
str = str.concat(String.fromCharCode(txt.charCodeAt(i).toUpperCase()));
}
Here's a quick function to do it. It makes the entire string lowercase and then iterates through the string with a step of 2 to make every other character uppercase.
var alternateCase = function (s) {
var chars = s.toLowerCase().split("");
for (var i = 0; i < chars.length; i += 2) {
chars[i] = chars[i].toUpperCase();
}
return chars.join("");
};
var txt = "hello world";
console.log(alternateCase(txt));
HeLlO WoRlD
The reason it converts the string to an array is to make the individual characters easier to manipulate (i.e. no need for String.prototype.concat()).
Here an ES6 approach:
function swapCase(text) {
return text.split('').map((c,i) =>
i % 2 == 0 ? c.toLowerCase() : c.toUpperCase()
).join('');
}
console.log(swapCase("test"))
You should iterate the string and alternate between upper-casing the character and lower-casing it:
for (var i=0; i<txt.length; i++) {
var ch = String.fromCharCode(txt.charCodeAt(i);
if (i % 2 == 1) {
ch = ch.toUpperCase();
} else {
ch = ch.toLowerCase();
}
str = str.concat(ch);
}

Javascript: Split a string by comma, except inside parentheses

Given string in the form:
'"abc",ab(),c(d(),e()),f(g(),zyx),h(123)'
How can I split it to get the below array format:
abc
ab()
c(d(),e())
f(g(),zyx)
h(123)
I have tried normal javascript split, however it doesn't work as desired. Trying Regular Expression but not yet successful.
You can keep track of the parentheses, and add those expressions when the left and right parens equalize.
For example-
function splitNoParen(s){
var left= 0, right= 0, A= [],
M= s.match(/([^()]+)|([()])/g), L= M.length, next, str= '';
for(var i= 0; i<L; i++){
next= M[i];
if(next=== '(')++left;
else if(next=== ')')++right;
if(left!== 0){
str+= next;
if(left=== right){
A[A.length-1]+=str;
left= right= 0;
str= '';
}
}
else A=A.concat(next.match(/([^,]+)/g));
}
return A;
}
var s1= '"abc",ab(),c(d(),e()),f(g(),zyx),h(123)';
splitNoParen(s1).join('\n');
/* returned value: (String)
"abc"
ab()
c(d(),e())
f(g(),zyx)
h(123)
*/
This might be not the best or more refined solution, and also maybe won't fit every single possibility, but based on your example it works:
var data = '"abc",ab(),c(d(),e()),f(g(),zyx),h(123)';
// Create a preResult splitting the commas.
var preResult = data.replace(/"/g, '').split(',');
// Create an empty result.
var result = [];
for (var i = 0; i < preResult.length; i++) {
// Check on every preResult if the number of parentheses match.
// Opening ones...
var opening = preResult[i].match(/\(/g) || 0;
// Closing ones...
var closing = preResult[i].match(/\)/g) || 0;
if (opening != 0 &&
closing != 0 &&
opening.length != closing.length) {
// If the current item contains a different number of opening
// and closing parentheses, merge it with the next adding a
// comma in between.
result.push(preResult[i] + ',' + preResult[i + 1]);
i++;
} else {
// Leave it as it is.
result.push(preResult[i]);
}
}
Demo
For future reference, here's another approach to top-level splitting, using string.replace as a control flow operator:
function psplit(s) {
var depth = 0, seg = 0, rv = [];
s.replace(/[^(),]*([)]*)([(]*)(,)?/g,
function (m, cls, opn, com, off, s) {
depth += opn.length - cls.length;
var newseg = off + m.length;
if (!depth && com) {
rv.push(s.substring(seg, newseg - 1));
seg = newseg;
}
return m;
});
rv.push(s.substring(seg));
return rv;
}
console.log(psplit('abc,ab(),c(d(),e()),f(g(),zyx),h(123)'))
["abc", "ab()", "c(d(),e())", "f(g(),zyx)", "h(123)"]
Getting it to handle quotes as well would not be too complicated, but at some point you need to decide to use a real parser such as jison, and I suspect that would be the point. In any event, there's not enough detail in the question to know what the desired handling of double quotes is.
You can't use .split for this, but instead you'll have to write a small parser like this:
function splitNoParen(s){
let results = [];
let next;
let str = '';
let left = 0, right = 0;
function keepResult() {
results.push(str);
str = '';
}
for(var i = 0; i<s.length; i++) {
switch(s[i]) {
case ',':
if((left === right)) {
keepResult();
left = right = 0;
} else {
str += s[i];
}
break;
case '(':
left++;
str += s[i];
break;
case ')':
right++;
str += s[i];
break;
default:
str += s[i];
}
}
keepResult();
return results;
}
var s1= '"abc",ab(),c(d(),e()),f(g(),zyx),h(123)';
console.log(splitNoParen(s1).join('\n'));
var s2='cats,(my-foo)-bar,baz';
console.log(splitNoParen(s2).join('\n'));
Had a similar issue and existing solutions were hard to generalize. So here's another parser that's a bit more readable and easier to extend to your personal needs. It'll also work with curly braces, brackets, normal braces, and strings of any type. License is MIT.
/**
* This function takes an input string and splits it by the given token, but only if the token is not inside
* braces of any kind, or a string.
* #param {string} input The string to split.
* #param {string} split_by Must be a single character.
* #returns {string[]} An array of split parts without the split_by character.
*/
export function parse_split(input:string, split_by:string = ",") : string[]
{
// Javascript has 3 types of strings
const STRING_TYPES = ["'","`","\""] as const;
// Some symbols can be nested, like braces, and must be counted
const state = {"{":0,"[":0,"(":0};
// Some cannot be nested, like a string, and just flip a flag.
// Additionally, once the string flag has been flipped, it can only be unflipped
// by the same token.
let string_state : (typeof STRING_TYPES)[number] | undefined = undefined
// Nestable symbols come in sets, usually in pairs.
// These sets increase or decrease the state, depending on the symbol.
const pairs : Record<string,[keyof typeof state,number]> = {
"{":["{",1],
"}":["{",-1],
"[":["[",1],
"]":["[",-1],
"(":["(",1],
")":["(",-1]
}
let start = 0;
let results = [];
let length = input.length;
for(let i = 0; i < length; ++i)
{
let char = input[i];
// Backslash escapes the next character. We directly skip 2 characters by incrementing i one extra time.
if(char === "\\")
{
i++;
continue;
}
// If the symbol exists in the single/not nested state object, flip the corresponding state flag.
if(char == string_state)
{
string_state = undefined;
console.log("Closed string ", string_state);
}
// if it's not in a string, but it's a string opener, remember the string type in string_state.
else if(string_state === undefined && STRING_TYPES.includes(char as typeof STRING_TYPES[number]))
{
string_state = char as typeof STRING_TYPES[number];
}
// If it's not in a string, and if it's a paired symbol, increase or decrease the state based on our "pairs" constant.
else if(string_state === undefined && (char in pairs) )
{
let [key,value] = pairs[char];
state[key] += value;
}
// If it's our split symbol...
else if(char === split_by)
{
// ... check whether any flags are active ...
if(Object.entries(state).every(([k,v])=>v == 0) && (string_state === undefined))
{
// ... if not, then this is a valid split.
results.push(input.substring(start,i))
start = i+1;
}
}
}
// Add the last segment if the string didn't end in the split_by symbol, otherwise add an empty string
if(start < input.length)
{
results.push(input.substring(start,input.length))
}
else
results.push("");
return results;
}
With this regex, it makes the job:
const regex = /,(?![^(]*\))/g;
const str = '"abc",ab(),c(d(),e()),f(g(),zyx),h(123)';
const result = str.split(regex);
console.log(result);
Javascript
var str='"abc",ab(),c(d(),e()),f(g(),zyx),h(123)'
str.split('"').toString().split(',').filter(Boolean);
this should work

pass $` value to associated parameter function of replace

I have an expression say
log(1,3)+4,5+max(7,8,9)
where comma is being used two ways.
1- In "log(1,3)+4,5" comma is being used in place of dot(.) or decimal sign.i.e. "log(1,3)+4,5" is equivalent to "log(1.3)+4.5".
2- In max(7,8,9) it is being used as number separator. i.e. this outcome of this is 9 ; the maximum number.
My problem is to substitute comma; which is being used as decimal separator; with decimal but this should not affect max(7,8,9). i.e. I need to convert above expression to
log(1.3)+4.5+max(7,8,9)
What I tried-
function substitute(expr) {
expr.replace(/,/g, function ($`) {
/*some processing here to decide whether comma to be substituted with dot or not.On that basis I will return either dot or comma.*/
}
But how can I pass $` value to associated function
or
Is it possible to do this in javascript.
expr.replace(/,/g,function ($`) {
if yes then how?
Your language is ambiguous.
max(8,1,8,2)
Does this return 8, 8,1 or 8,2?
Your language also doesn't look regular, so you can't parse it with a regular expression, you need the context. If something like this is allowed:
max(1,max(2,3)) // 3?
Assuming you can get rid of the ambiguity, you could write a parser to do the context detection.
This could be a solution :
function myFilter(string) {
// save all functions and signs
var functions = [];
var regExp = /[+,-]max\(([^\)]+)\)/;
matches = true;
while (matches !== null) {
var matches = regExp.exec(string);
if (matches !== null) {
functions.push(matches[0]);
string = string.replace(matches[0], '');
}
}
// replace all remaining commas with dots
string = string.replace(/,/g , ".");
for (i in functions) {
string += functions[i];
}
return string;
}
var s = '1,3+4,5+max(7,8,9)-max(2,3,5)';
var filteredString = myFilter(s);
jsFiddle Demo
This currently works with multiple max functions but only + and - signs. It could be improved with *, / and more... You will have to find the good regex.
Try the below using Javascript. Hope this helps you in logic.
DEMO HERE
var value = "log(1,3)-4,5+max(7,8,9)";
var val = '';
var splitValue, appendSym;
if (value.indexOf("+") != -1)
{
splitValue = value.split("+");
appendSym = "+";
}
else if(value.indexOf("-") != -1)
{
splitValue = value.split("-");
appendSym = "-";
}
else if(value.indexOf("*") != -1)
{
splitValue = value.split("*");
appendSym = "*";
}
else
{
splitValue = value.split("/");
appendSym = "/";
}
var length = splitValue.length;
for (var i = 0; i < length; i++) {
if (val) val += appendSym;
var strrep = splitValue[i].replace(/,/g,".");
if (splitValue[i].indexOf("max") != -1 || splitValue[i].indexOf("min") != -1)
{
val+=splitValue[i];
}
else
{
val+=strrep;
}
}
alert(val);
The output for the above code is log(1.3)-4.5+max(7,8,9)

Javascript in list

What's the easiest way to check to see if a number is in a comma delimited list?
console.log(provider[cardType]);
//returns: Object { name="visa", validLength="16,13", prefixRegExp=}
if (ccLength == 0 || (cardType > 0 && ccLength < provider[cardType].validLength)) {
triggerNotification('x', 'Your credit card number isn\'t long enough');
return false;
} else {
if ($('.credit-card input[name="cc_cvv"]').val().length < 3) {
triggerNotification('x', 'You must provide a CCV');
return false;
}
Seems similar to this SO question.
Just .split() the CSV and use inArray.
Not sure how your sample code relates to checking to see if a number is in a comma delimited list...
Also not sure if this is the easiest way, but it's what springs to mind:
<script type="text/javascript">
var myNumbers = "1,2,3,4,5";
var myArray = myNumbers.split( ',' );
// looking for "4"
for ( var i=0; i<myArray.length; i++ ) {
if (myArray[i] == 4) {
alert('Found it!');
break;
}
}
I do not see where you have a significant comma delimited list in the script you posted.
The fastest way could be something like
var csvList ="a,b,c,d,e,f,g,h";
var testList = ","+csvList+",";
var needle = "f";
alert(testList.indexOf(","+needle+",")!=-1)
just to be different ;)
If it's just a list of comma separated numbers with nothing fancy, you can just use the split method:
var numbers = list.split(",");
This will give you an array of all of the numbers in the list. Checking whether a number is in an array is trivial.
Native JavaScript and therefore cross-browser compliant. Some frameworks provide functions that do this for you, but you don't get more basic than the following.
var numbers = list.split(",");
var count = numbers.length;
var exists = false;
for (var i = 0; i < count; ++i) {
if (numbers[i] == anumber) {
exists = true;
break;
}
}
From your sample, I assume your question was "How do I see if a number is within a range of two values specified by a single-comma-delimited string?":
function inRange( number, stringRange ){
var minmax = stringRange.split(',');
minmax[0] = minmax[0]*1; //convert to number
minmax[1] = minmax[1]*1; //convert to number
minmax.sort(); // Ensure [0] is the min
return number>=minmax[0] && number<=minmax[1];
}
Try this one...
console.log(provider[cardType]); //returns: Object { name="visa", validLength="16,13", prefixRegExp=}
var regExp = new RegExp(",?" + ccLength + ",?");
if (ccLength == 0 || (cardType > 0 && !regExp.test(provider[cardType].validLength)))
{
triggerNotification('x', 'Your credit card number isn\'t long enough');
return false;
}
else
{
if ($('.credit-card input[name="cc_cvv"]').val().length < 3)
{
triggerNotification('x', 'You must provide a CCV');
return false;
}
}

Javascript word-count for any given DOM element

I'm wondering if there's a way to count the words inside a div for example. Say we have a div like so:
<div id="content">
hello how are you?
</div>
Then have the JS function return an integer of 4.
Is this possible? I have done this with form elements but can't seem to do it for non-form ones.
Any ideas?
g
If you know that the DIV is only going to have text in it, you can KISS:
var count = document.getElementById('content').innerHTML.split(' ').length;
If the div can have HTML tags in it, you're going to have to traverse its children looking for text nodes:
function get_text(el) {
ret = "";
var length = el.childNodes.length;
for(var i = 0; i < length; i++) {
var node = el.childNodes[i];
if(node.nodeType != 8) {
ret += node.nodeType != 1 ? node.nodeValue : get_text(node);
}
}
return ret;
}
var words = get_text(document.getElementById('content'));
var count = words.split(' ').length;
This is the same logic that the jQuery library uses to achieve the effect of its text() function. jQuery is a pretty awesome library that in this case is not necessary. However, if you find yourself doing a lot of DOM manipulation or AJAX then you might want to check it out.
EDIT:
As noted by Gumbo in the comments, the way we are splitting the strings above would count two consecutive spaces as a word. If you expect that sort of thing (and even if you don't) it's probably best to avoid it by splitting on a regular expression instead of on a simple space character. Keeping that in mind, instead of doing the above split, you should do something like this:
var count = words.split(/\s+/).length;
The only difference being on what we're passing to the split function.
Paolo Bergantino's second solution is incorrect for empty strings or strings that begin or end with whitespaces. Here's the fix:
var count = !s ? 0 : (s.split(/^\s+$/).length === 2 ? 0 : 2 +
s.split(/\s+/).length - s.split(/^\s+/).length - s.split(/\s+$/).length);
Explanation: If the string is empty, there are zero words; If the string has only whitespaces, there are zero words; Else, count the number of whitespace groups without the ones from the beginning and the end of the string.
string_var.match(/[^\s]+/g).length
seems like it's a better method than
string_var.split(/\s+/).length
At least it won't count "word " as 2 words -- ['word'] rather than ['word', '']. And it doesn't really require any funny add-on logic.
Or just use Countable.js to do the hard job ;)
document.deepText= function(hoo){
var A= [];
if(hoo){
hoo= hoo.firstChild;
while(hoo!= null){
if(hoo.nodeType== 3){
A[A.length]= hoo.data;
}
else A= A.concat(arguments.callee(hoo));
hoo= hoo.nextSibling;
}
}
return A;
}
I'd be fairly strict about what a word is-
function countwords(hoo){
var text= document.deepText(hoo).join(' ');
return text.match(/[A-Za-z\'\-]+/g).length;
}
alert(countwords(document.body))
Or you can do this:
function CountWords (this_field, show_word_count, show_char_count) {
if (show_word_count == null) {
show_word_count = true;
}
if (show_char_count == null) {
show_char_count = false;
}
var char_count = this_field.value.length;
var fullStr = this_field.value + " ";
var initial_whitespace_rExp = /^[^A-Za-z0-9]+/gi;
var left_trimmedStr = fullStr.replace(initial_whitespace_rExp, "");
var non_alphanumerics_rExp = rExp = /[^A-Za-z0-9]+/gi;
var cleanedStr = left_trimmedStr.replace(non_alphanumerics_rExp, " ");
var splitString = cleanedStr.split(" ");
var word_count = splitString.length -1;
if (fullStr.length <2) {
word_count = 0;
}
if (word_count == 1) {
wordOrWords = " word";
} else {
wordOrWords = " words";
}
if (char_count == 1) {
charOrChars = " character";
} else {
charOrChars = " characters";
}
if (show_word_count & show_char_count) {
alert ("Word Count:\n" + " " + word_count + wordOrWords + "\n" + " " + char_count + charOrChars);
} else {
if (show_word_count) {
alert ("Word Count: " + word_count + wordOrWords);
} else {
if (show_char_count) {
alert ("Character Count: " + char_count + charOrChars);
}
}
}
return word_count;
}
The get_text function in Paolo Bergantino's answer didn't work properly for me when two child nodes have no space between them. eg <h1>heading</h1><p>paragraph</p> would be returned as headingparagraph (notice lack of space between the words). So prepending a space to the nodeValue fixes this. But it introduces a space at the front of the text but I found a word count function that trims it off (plus it uses several regexps to ensure it counts words only). Word count and edited get_text functions below:
function get_text(el) {
ret = "";
var length = el.childNodes.length;
for(var i = 0; i < length; i++) {
var node = el.childNodes[i];
if(node.nodeType != 8) {
ret += node.nodeType != 1 ? ' '+node.nodeValue : get_text(node);
}
}
return ret;
}
function wordCount(fullStr) {
if (fullStr.length == 0) {
return 0;
} else {
fullStr = fullStr.replace(/\r+/g, " ");
fullStr = fullStr.replace(/\n+/g, " ");
fullStr = fullStr.replace(/[^A-Za-z0-9 ]+/gi, "");
fullStr = fullStr.replace(/^\s+/, "");
fullStr = fullStr.replace(/\s+$/, "");
fullStr = fullStr.replace(/\s+/gi, " ");
var splitString = fullStr.split(" ");
return splitString.length;
}
}
EDIT
kennebec's word counter is really good. But the one I've found includes a number as a word which is what I needed. Still, that's easy to add to kennebec's. But kennebec's text retrieval function will have the same problem.
This should account for preceding & trailing whitespaces
const wordCount = document.querySelector('#content').innerText.trim().split(/\s+/).length;
string_var.match(/[^\s]+/g).length - 1;

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