Develop Reference

Regex replace for multiple matches

Trying to figure out a Regex to inject and remove a string (in this case var.par_) at the following locations:
Very Beginning
After ^
After ^OR
Example input string when injecting:
job=developer^language=js^ORlanguage=react^ORlanguageSTARTSWITHjava
Should result in output of
var.par_job=developer^var.par_language=js^ORvar.par_language=react^ORvar.par_languageSTARTSWITHjava
and vice versa when removing:
var.par_language=react^ORvar.par_languageSTARTSWITHjava
should result in
language=react^ORlanguageSTARTSWITHjava
My current feeble attempt was this:
var input = "job=developer^language=js^ORlanguage=react^ORlanguageSTARTSWITHjava";
const replaceToken = "var.par_";
var output = input.replace(/^()?/, replaceToken).replace(/\^()?/g, '^' + replaceToken);

let input = "job=developer^language=js^ORlanguage=react^ORlanguageSTARTSWITHjava";
const replaceToken = "var.par_";
let output = input.replace(/^|\^OR|\^/g, '$&' + replaceToken);
console.log(output)
The regexp /^|\^OR|\^/ matches each of your locations. $& in the replacement gets replaced with the match. So there's no need to use multiple calls to .replace().

How to replace numbers with an empty char

i need to replace phone number in string on \n new line.
My string: Jhony Jhons,jhon#gmail.com,380967574366
I tried this:
var str = 'Jhony Jhons,jhon#gmail.com,380967574366'
var regex = /[0-9]/g;
var rec = str.trim().replace(regex, '\n').split(','); //Jhony Jhons,jhon#gmail.com,
Number replace on \n but after using e-mail extra comma is in the string need to remove it.
Finally my string should look like this:
Jhony Jhons,jhon#gmail.com\n

You can try this:
var str = 'Jhony Jhons,jhon#gmail.com,380967574366';
var regex = /,[0-9]+/g;
str.replace(regex, '\n');
The snippet above may output what you want, i.e. Jhony Jhons,jhon#gmail.com\n

There's a lot of ways to that, and this is so easy, so try this simple answer:-
var str = 'Jhony Jhons,jhon#gmail.com,380967574366';
var splitted = str.split(","); //split them by comma
splitted.pop(); //removes the last element
var rec = splitted.join() + '\n'; //join them

You need a regex to select the complete phone number and also the preceding comma. Your current regex selects each digit and replaces each one with an "\n", resulting in a lot of "\n" in the result. Also the regex does not match the comma.
Use the following regex:
var str = 'Jhony Jhons,jhon#gmail.com,380967574366'
var regex = /,[0-9]+$/;
// it replaces all consecutive digits with the condition at least one digit exists (the "[0-9]+" part)
// placed at the end of the string (the "$" part)
// and also the digits must be preceded by a comma (the "," part in the beginning);
// also no need for global flag (/g) because of the $ symbol (the end of the string) which can be matched only once
var rec = str.trim().replace(regex, '\n'); //the result will be this string: Jhony Jhons,jhon#gmail.com\n

var str = "Jhony Jhons,jhon#gmail.com,380967574366";
var result = str.replace(/,\d+/g,'\\n');
console.log(result)

how can i replace first two characters of a string in javascript?

lets suppose i have string
var string = "$-20455.00"
I am trying to swap first two characters of a string. I was thinking to split it and make an array and then replacing it, but is there any other way? Also, I am not clear how can I achieve it using arrays? if I have to use arrays.
var string = "-$20455.00"
How can I achieve this?

You can use the replace function in Javascript.
var string = "$-20455.00"
string = string.replace(/^.{2}/g, 'rr');
Here is jsfiddle: https://jsfiddle.net/aoytdh7m/33/

You dont have to use arrays. Just do this
string[1] + string[0] + string.slice(2)

You can split to an array, and then reverse the first two characters and join the pieces together again
var string = "$-20455.00";
var arr = string.split('');
var result = arr.slice(0,2).reverse().concat(arr.slice(2)).join('');
document.body.innerHTML = result;

try using the "slice" method and string concatenation:
stringpart1 = '' //fill in whatever you want to replace the first two characters of the first string with here
string2 = stringpart1 + string.slice(1)
edit: I now see what you meant by "swap". I thought you meant "swap in something else". Vlad's answer is best to just switch the first and the second character.
Note that string[0] refers to the first character in the string, and string[1] to the second character, and so on, because code starts counting at 0.

var string = "$-20455.00";
// Reverse first two characters
var reverse = string.slice(0,2).split('').reverse().join('');
// Concat again with renaming string
var result= reverse.concat(string.slice(2));
document.body.innerHTML = result;

let finalStr = string[1] + string[0] + string.slice(2); //this will give you the result

How to convert string from textbox into a number using javascript?

I have a textbox with input value of 20,466,000.00 . I want to return only the value of 20466000 without a comma and a decimal point. I tried the following :
// Get value
var nca_balance = $("#nca-balance").text();
var nca_amount = parseInt(nca_balance.replace(",", ""),10);
alert(nca_amount);
But it only returns the value of 20466 ? Why ? My expected result must be 20466000. Please help with my code. Thanks

How about this one:
parseInt("20,466,000.00".replace(/,/g, ""), 10)

Because replace is replacing the first comma by default use g as global option in replace regular expression /,/g like,
var nca_balance = $("#nca-balance").text();
var nca_amount = parseInt(nca_balance.replace(/,/g, ""),10);
alert(nca_amount);
var nca_balance = $("#nca-balance").text();
var nca_amount = parseInt(nca_balance.replace(/,/g, ""), 10);
alert(nca_amount);
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<span id="nca-balance">20,466,000.00<span>

You have to use regular expression instead of replace function because replace function will replace only first matching character.
nca_balance = "20,466,000.00";
var nca_amount = parseInt(nca_balance.replace(/,/g, ''));
alert(nca_amount);
Regular expression /,/g will replace all comma with your provided character globally.

Put quotes around a variable string in JavaScript

I have a JavaScript variable:
var text = "http://example.com"
Text can be multiple links. How can I put '' around the variable string?
I want the strings to, for example, look like this:
"'http://example.com'"

var text = "\"http://example.com\"";
Whatever your text, to wrap it with ", you need to put them and escape inner ones with \. Above will result in:
"http://example.com"

var text = "http://example.com";
text = "'"+text+"'";
Would attach the single quotes (') to the front and the back of the string.

I think, the best and easy way for you, to put value inside quotes is:
JSON.stringify(variable or value)

You can add these single quotes with template literals:
var text = "http://example.com"
var quoteText = `'${text}'`
console.log(quoteText)
Docs are here. Browsers that support template literals listed here.

Try:
var text = "'" + "http://example.com" + "'";

To represent the text below in JavaScript:
"'http://example.com'"
Use:
"\"'http://example.com'\""
Or:
'"\'http://example.com\'"'
Note that: We always need to escape the quote that we are surrounding the string with using \
JS Fiddle: http://jsfiddle.net/efcwG/
General Pointers:
You can use quotes inside a string, as long as they don't match the
quotes surrounding the string:
Example
var answer="It's alright";
var answer="He is called 'Johnny'";
var answer='He is called "Johnny"';
Or you can put quotes inside a string by using the \ escape
character:
Example
var answer='It\'s alright';
var answer="He is called \"Johnny\"";
Or you can use a combination of both as shown on top.
http://www.w3schools.com/js/js_obj_string.asp

let's think urls = "http://example1.com http://example2.com"
function somefunction(urls){
var urlarray = urls.split(" ");
var text = "\"'" + urlarray[0] + "'\"";
}
output will be text = "'http://example1.com'"

In case of array like
result = [ '2015', '2014', '2013', '2011' ],
it gets tricky if you are using escape sequence like:
result = [ \'2015\', \'2014\', \'2013\', \'2011\' ].
Instead, good way to do it is to wrap the array with single quotes as follows:
result = "'"+result+"'";

You can escape " with \
var text="\"word\"";
http://jsfiddle.net/beKpE/

Lets assume you have a bunch of urls separated by spaces. In this case, you could do this:
function quote(text) {
var urls = text.split(/ /)
for (var i = 0; i < urls.length; i++) urls[i] = "'" + urls[i] + "'"
return urls.join(" ")
}
This function takes a string like "http://example.com http://blarg.test" and returns a string like "'http://example.com' 'http://blarg.test'".
It works very simply: it takes your string of urls, splits it by spaces, surrounds each resulting url with quotes and finally combines all of them back with spaces.

var text = "\"http://www.example1.com\"; \"http://www.example2.com\"";
Using escape sequence of " (quote), you can achieve this
You can place singe quote (') inside double quotes without any issues
Like this
var text = "'http://www.ex.com';'http://www.ex2.com'"

Another easy way to wrap a string is to extend the Javascript String prototype:
String.prototype.quote = function() { return "\"" + this + "\""; };
Use it like this:
var s = "abc";
console.log( "unwrapped: " + s + ", wrapped: " + s.quote() );
and you will see:
unwrapped: abc, wrapped: "abc"

This can be one of several solutions:
var text = "http://example.com";
JSON.stringify(text).replace('\"', '\"\'').replace(/.$/, '\'"')