We Keep Coding

Get length of characters between two matching charcaters in a string in javascript

For Example if input string is "Bcoica",
the length of string between matching characters (between two c's) should return 2

You may try out as,
let mystr = "Bracelet";
function distanceBetweenDuplicateCharacters(char,str){
return str.substr( str.indexOf(char) + 1 ).indexOf(char);
};
console.log(distanceBetweenDuplicateCharacters('e',mystr));

You could use String#indexOf with a starting index.
var string = 'Bcoica',
first = string.indexOf('c'),
second = string.indexOf('c', first + 1);
console.log(second - first - 1);

This is a way you can approach this problem.
Just use indexOf and make a prototype with it for conveniecnce.
var string = "Bcoica";
String.prototype.sizeBetween = function(startChar, endChar) {
//we first get the position of the first char in string
var target = this;
if(startChar===endChar){ // if it's equal we go to the next character
startChar = target.indexOf(startChar);
endChar = target.indexOf(endChar, startChar+1)
} else {
startChar = target.indexOf(startChar);
endChar = target.indexOf(endChar);
}
return endChar-startChar-1; //just return the diference between the two numbers
};
console.log(string.sizeBetween("c","c"));

how to remove array String substring() Method using javascript?

I would like to know how can I remove the First word in the string using JavaScript?
For example, the string is "mod1"
I want to remove mod..I need to display 1
var $checked = $('.dd-list').find('.ModuleUserViews:checked');
var modulesIDS = [];
$checked.each(function (index) { modulesIDS.push($(this).attr("id")); })

You can just use the substring method. The following will give the last character of the string.
var id = "mod1"
var result = id.substring(id.length - 1, id.length);
console.log(result)

Try this.
var arr = ["mod1"];
var replaced= $.map( arr, function( a ) {
return a.replace("mod", "");
});
console.log(replaced);

If you want to remove all letters and keep only the numbers in the string, you can use a regex match.
var str = "mod125lol";
var nums = str.match(/\d/g).join('');
console.log(nums);
// "125"

If you don't want to split the string (faster, less memory consumed), you can use indexOf() with substr():
var id = "mod1"
var result = id.substr(id.indexOf(" ") -0);
console.log(result)

How to capitalize the last letter of each word in a string

I am still rather new to JavaScript and I am having an issue of getting the first character of the string inside the array to become uppercase.
I have gotten to a point where I have gotten all the texted lowercase, reversed the text character by character, and made it into a string. I need to get the first letter in the string to uppercase now.
function yay () {
var input = "Party like its 2015";
return input.toLowerCase().split("").reverse().join("").split(" ");
for(var i = 1 ; i < input.length ; i++){
input[i] = input[i].charAt(0).toUpperCase() + input[i].substr(1);
}
}
console.log(yay());
I need the output to be "partY likE itS 2015"

Frustrating that you posted your initial question without disclosing the desired result. Lots of turmoil because of that. Now, that the desired result is finally clear - here's an answer.
You can lowercase the whole thing, then split into words, rebuild each word in the array by uppercasing the last character in the word, then rejoin the array:
function endCaseWords(input) {
return input.toLowerCase().split(" ").map(function(item) {
return item.slice(0, -1) + item.slice(-1).toUpperCase();
}).join(" ");
}
document.write(endCaseWords("Party like its 2015"));
Here's a step by step explanation:
Lowercase the whole string
Use .split(" ") to split into an array of words
Use .map() to iterate the array
For each word, create a new word that is the first part of the word added to an uppercased version of the last character in the word
.join(" ") back together into a single string
Return the result
You could also use a regex replace with a custom callback:
function endCaseWords(input) {
return input.toLowerCase().replace(/.\b/g, function(match) {
return match.toUpperCase();
});
}
document.write(endCaseWords("Party like its 2015"));
FYI, there are lots of things wrong with your original code. The biggest mistake is that as soon as you return in a function, no other code in that function is executed so your for loop was never executed.
Then, there's really no reason to need to reverse() the characters because once you split into words, you can just access the last character in each word.

Instead of returning the result splitting and reversing the string, you need to assign it to input. Otherwise, you return from the function before doing the loop that capitalizes the words.
Then after the for loop you should return the joined string.
Also, since you've reverse the string before you capitalize, you should be capitalizing the last letter of each word. Then you need to reverse the array before re-joining it, to get the words back in the original order.
function yay () {
var input = "Party like its 2015";
input = input.toLowerCase().split("").reverse().join("").split(" ");
for(var i = 1 ; i < input.length ; i++){
var len = input[i].length-1;
input[i] = input[i].substring(0, len) + input[i].substr(len).toUpperCase();
}
return input.reverse().join(" ");
}
alert(yay());

You can use regular expression for that:
input.toLowerCase().replace(/[a-z]\b/g, function (c) { return c.toUpperCase() });
Or, if you can use arrow functions, simply:
input.toLowerCase().replace(/[a-z]\b/g, c => c.toUpperCase())

Here's what I would do:
Split the sentence on the space character
Transform the resulting array using .map to capitalize the first character and lowercase the remaining ones
Join the array on a space again to get a string
function yay () {
var input = "Party like its 2015";
return input.split(" ").map(function(item) {
return item.charAt(0).toUpperCase() + item.slice(1).toLowerCase();
}).join(" ");
}
console.log(yay());

Some ugly, but working code:
var text = "Party like its 2015";
//partY likE itS 2015
function yay(input) {
input = input.split(' ');
arr = [];
for (i = 0; i < input.length; i++) {
new_inp = input[i].charAt(0).toLowerCase() + input[i].substring(1, input[i].length - 1) + input[i].charAt(input[i].length - 1).toUpperCase();
arr.push(new_inp);
}
str = arr.join(' ');
return str;
}
console.log(yay(text));

Try using ucwords from PHP.js. It's quite simple, actually.
String.prototype.ucwords = function() {
return (this + '')
.replace(/^([a-z\u00E0-\u00FC])|\s+([a-z\u00E0-\u00FC])/g, function($1) {
return $1.toUpperCase();
});
}
var input = "Party like its 2015";
input = input.charAt(0).toLowerCase() + input.substr(1);
input = input.split('').reverse().join('').ucwords();
input = input.split('').reverse().join('');
Note: I modified their function to be a String function so method chaining would work.

function yay(str)
{
let arr = str.split(' ');
let farr = arr.map((item) =>{
let x = item.split('');
let len = x.length-1
x[len] = x[len].toUpperCase();
x= x.join('')
return x;
})
return farr.join(' ')
}
var str = "Party like its 2015";
let output = yay(str);
console.log(output) /// "PartY likE itS 2015"

You can split and then map over the array perform uppercase logic and retun by joining string.
let string = "Party like its 2015";
const yay = (string) => {
let lastCharUpperCase = string.split(" ").map((elem) => {
elem = elem.toLowerCase();
return elem.replace(elem[elem.length - 1], elem[elem.length - 1].toUpperCase())
})
return lastCharUpperCase.join(" ");
}
console.log(yay(string))

how to replace multiple special character in a number?

I have a number say 2,500.00 and i want to convert the number into 2.500,00. So, we can replace the special character using replace like
var x = 2,500.00;
x.replace(/,/g,".");
and for "Dot" also, we can do it. But in this case, it won't work because when we apply replace function for comma as above, the number will become 2.500.00 and if we apply now, it will become as 2,500,00.
So is there any way to convert 2,500.00 into 2.500,00 ?

String.prototype.replace can take a function:
'2,123,500.00'.replace(/[,.]/g, function(c){ return c===',' ? '.' : ','; });

You can use:
var x = '2,123,500.00';
var arr = x.split('.');
var y = arr[0].replace(/,/g, '.') + ',' + arr[1];
//=> 2.123.500,00

You're in luck, .replace() accept a function as second argument. That function has the matched string as argument and the returned value will be the replace_by value of .replace().
In short, you can simply check what the matched string is and return the right value :
var str = "2,500.00";
var changed_str = str.replace(/,|\./g, function(old){
if (old === '.')
return ',';
else if (old === ',')
return '.';
});
document.write(changed_str)

Why not use the built-in methods to format your numbers correctly?
Number.toLocaleString() would work just fine here.
If you actually have a number as you said, you can easily achieve this using the right locale. If you have a String representation of your number, you would first have to parse it.

This (now) works for any number of commas or dots, even if trailing or leading dots or commas.
HTML:
<div id="result"></div>
JS:
var x = '.,2.123,50.0.00.';
var between_dots = x.split('.');
for (var i = 0; i < between_dots.length; i++) {
between_dots[i] = between_dots[i].replace(/,/g, '.');
}
var y = between_dots.join(',');
document.getElementById('result').innerHTML = y;
Here's the JSFiddle

Delete first character of string if it is 0

I want to delete the first character of a string, if the first character is a 0. The 0 can be there more than once.
Is there a simple function that checks the first character and deletes it if it is 0?
Right now, I'm trying it with the JS slice() function but it is very awkward.

You can remove the first character of a string using substring:
var s1 = "foobar";
var s2 = s1.substring(1);
alert(s2); // shows "oobar"
To remove all 0's at the start of the string:
var s = "0000test";
while(s.charAt(0) === '0')
{
s = s.substring(1);
}

Very readable code is to use .substring() with a start set to index of the second character (1) (first character has index 0). Second parameter of the .substring() method is actually optional, so you don't even need to call .length()...
TL;DR : Remove first character from the string:
str = str.substring(1);
...yes it is that simple...
Removing some particular character(s):
As #Shaded suggested, just loop this while first character of your string is the "unwanted" character...
var yourString = "0000test";
var unwantedCharacter = "0";
//there is really no need for === check, since we use String's charAt()
while( yourString.charAt(0) == unwantedCharacter ) yourString = yourString.substring(1);
//yourString now contains "test"
.slice() vs .substring() vs .substr()
EDIT: substr() is not standardized and should not be used for new JS codes, you may be inclined to use it because of the naming similarity with other languages, e.g. PHP, but even in PHP you should probably use mb_substr() to be safe in modern world :)
Quote from (and more on that in) What is the difference between String.slice and String.substring?
He also points out that if the parameters to slice are negative, they
reference the string from the end. Substring and substr doesn´t.

Use .charAt() and .slice().
Example: http://jsfiddle.net/kCpNQ/
var myString = "0String";
if( myString.charAt( 0 ) === '0' )
myString = myString.slice( 1 );
If there could be several 0 characters at the beginning, you can change the if() to a while().
Example: http://jsfiddle.net/kCpNQ/1/
var myString = "0000String";
while( myString.charAt( 0 ) === '0' )
myString = myString.slice( 1 );

The easiest way to strip all leading 0s is:
var s = "00test";
s = s.replace(/^0+/, "");
If just stripping a single leading 0 character, as the question implies, you could use
s = s.replace(/^0/, "");

You can do it with substring method:
let a = "My test string";
a = a.substring(1);
console.log(a); // y test string

Did you try the substring function?
string = string.indexOf(0) == '0' ? string.substring(1) : string;
Here's a reference - https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/substring
And you can always do this for multiple 0s:
while(string.indexOf(0) == '0')
{
string = string.substring(1);
}

One simple solution is to use the Javascript slice() method, and pass 1 as a parameter
let str = "khattak01"
let resStr = str.slice(1)
console.log(resStr)
Result : hattak01

var s = "0test";
if(s.substr(0,1) == "0") {
s = s.substr(1);
}
For all 0s: http://jsfiddle.net/An4MY/
String.prototype.ltrim0 = function() {
return this.replace(/^[0]+/,"");
}
var s = "0000test".ltrim0();

const string = '0My string';
const result = string.substring(1);
console.log(result);
You can use the substring() javascript function.

//---- remove first and last char of str
str = str.substring(1,((keyw.length)-1));
//---- remove only first char
str = str.substring(1,(keyw.length));
//---- remove only last char
str = str.substring(0,(keyw.length));

try
s.replace(/^0/,'')
console.log("0string =>", "0string".replace(/^0/,'') );
console.log("00string =>", "00string".replace(/^0/,'') );
console.log("string00 =>", "string00".replace(/^0/,'') );

Here's one that doesn't assume the input is a string, uses substring, and comes with a couple of unit tests:
var cutOutZero = function(value) {
if (value.length && value.length > 0 && value[0] === '0') {
return value.substring(1);
}
return value;
};
http://jsfiddle.net/TRU66/1/

String.prototype.trimStartWhile = function(predicate) {
if (typeof predicate !== "function") {
return this;
}
let len = this.length;
if (len === 0) {
return this;
}
let s = this, i = 0;
while (i < len && predicate(s[i])) {
i++;
}
return s.substr(i)
}
let str = "0000000000ABC",
r = str.trimStartWhile(c => c === '0');
console.log(r);

Another alternative to get the first character after deleting it:
// Example string
let string = 'Example';
// Getting the first character and updtated string
[character, string] = [string[0], string.substr(1)];
console.log(character);
// 'E'
console.log(string);
// 'xample'

From the Javascript implementation of trim() > that removes and leading or ending spaces from strings. Here is an altered implementation of the answer for this question.
var str = "0000one two three0000"; //TEST
str = str.replace(/^\s+|\s+$/g,'0'); //ANSWER
Original implementation for this on JS
string.trim():
if (!String.prototype.trim) {
String.prototype.trim = function() {
return this.replace(/^\s+|\s+$/g,'');
}
}

Another alternative answer
str.replace(/^0+/, '')

var test = '0test';
test = test.replace(/0(.*)/, '$1');