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Splitting a string at special character with JavaScript

I am trying to "intelligently" pre-fill a form, I want to prefill the firstname and lastname inputs based on a user email address, so for example,
jon.doe#email.com RETURNS Jon Doe
jon_doe#email.com RETURN Jon Doe
jon-doe#email.com RETURNS Jon Doe
I have managed to get the string before the #,
var email = letters.substr(0, letters.indexOf('#'));
But cant work out how to split() when the separator can be multiple values, I can do this,
email.split("_")
but how can I split on other email address valid special characters?

JavaScript's string split method can take a regex.
For example the following will split on ., -, and _.
"i-am_john.doe".split(/[.\-_]/)
Returning the following.
["i", "am", "john", "doe"]

You can use a regular expression for what you want to split on. You can for example split on anything that isn't a letter:
var parts = email.split(/[^A-Za-z]/);
Demo: http://jsfiddle.net/Guffa/xt3Lb9e6/

You can split a string using a regular expression. To match ., _ or -, you can use a character class, for example [.\-_]. The syntax for regular expressions in JavaScript is /expression/, so your example would look like:
email.split(/[\.\-_]/);
Note that the backslashes are to prevent . and - being interpreted as special characters. . is a special character class representing any character. In a character class, - can be used to specify ranges, such as [a-z].
If you require a dynamic list of characters to split on, you can build a regular expression using the RegExp constructor. For example:
var specialChars = ['.', '\\-', '_'];
var specialRegex = new RegExp('[' + specialChars.join('') + ']');
email.split(specialRegex);
More information on regular expressions in JavaScript can be found on MDN.

Regular Expressions --
email.split(/[_\.-]/)
This one matches (therefore splits at) any of (a character set, indicated by []) _, ., or -.
Here's a good resource for learning regular expressions: http://qntm.org/files/re/re.html

You can use regex to do it, just provide a list of the characters in square brackets and escape if necessary.
email.split("[_-\.]");
Is that what you mean?

You are correct that you need to use the split function.
Split function works by taking an argument to split the string on. Multiple values can be split via regular expression. For you usage, try something like
var re = /[\._\-]/;
var split = email.split(re, 2);
This should result in an array with two values, first/second name. The second argument is the number of elements returned.

I created a jsFiddle to show how this could be done :
function printName(email){
var name = email.split('#')[0];
// source : http://stackoverflow.com/questions/650022/how-do-i-split-a-string-with-multiple-separators-in-javascript
var returnVal = name.split(/[._-]/g);
return returnVal;
}
http://jsfiddle.net/ts6nx9tt/1/

If you define your seperators, below code can return all alternatives for you.
var arr = ["_",".","-"];
var email = letters.substr(0, letters.indexOf('#'));
arr.map(function(val,index,rest){
var r = email.split(val);
if(r.length > 1){
return r.join(' ');
}
return "";
}
);

Split each string from any given paragraph in javascript

I have a textArea. I am trying to split each string from a paragraph, which has proper grammar based punctuation delimiters like ,.!? or more if any.
I am trying to achieve this using Javascript. I am trying to get all such strings in that using the regular expression as in this answer
But here, in javascript for me it's not working. Here's my code snippet for more clarity
$('#split').click(function(){
var textAreaContent = $('#textArea').val();
//split the string i.e.., textArea content
var splittedArray = textAreaContent.split("\\W+");
alert("Splitted Array is "+splittedArray);
var lengthOfsplittedArray = splittedArray.length;
alert('lengthOfText '+lengthOfsplittedArray);
});
Since its unable to split, its always showing length as 1. What could be the apt regular expression here.

The regular expression shouldn't differ between Java and JavaScript, but the .split() method in Java accepts a regular expression string. If you want to use a regular expression in JavaScript, you need to create one...like so:
.split(/\W+/)
DEMO: http://jsfiddle.net/s3B5J/
Notice the / and / to create a regular expression literal. The Java version needed two "\" because it was enclosed in a string.
Reference:
https://developer.mozilla.org/en-US/docs/JavaScript/Guide/Regular_Expressions

You can try this
textAreaContent.split(/\W+/);

\W+ : Matches any character that is not a word character (alphanumeric & underscore).
so it counts except alphanumerics and underscore! if you dont need to split " " (space) then you can use;
var splittedArray = textAreaContent.split("/\n+/");

How to match a specific regular expression?

I am having a hard time understanding how to match a certain regular expression using javascripts match() function. I have a field in a table stored in the following format:
CH-01-Feb-13-1. I want to be able to grab the date without the dashes, i.e. 01-Feb-13. I was trying to figure out how to combine with ^- or . but not sure how to do it.

So you want the regular expression?
Something like
^\w{2}-(\d{2}-\w{3}-\d{2}).*?$
You can see the explanation here: http://www.regexper.com/ Just copy and paste the expression.
Example with Javascript
var r = /^\w{2}-(\d{2}-\w{3}-\d{2}).*?$/i
var groups = "CH-01-Feb-13-1".match(r);
console.log(groups);

If you are not comfortable with Regex then you can use something like this.
var str = 'CH-01-Feb-13-1';
str = str.replace('CH-','');
str = str.split('-');
str.pop();
console.log(str.join('-'));

Extracting numbers from a string using regular expressions

I am clueless about regular expressions, but I know that they're the right tool for what I'm trying to do here: I'm trying to extract a numerical value from a string like this one:
approval=not requested^assignment_group=12345678901234567890123456789012^category=Test^contact_type=phone^
Ideally, I'd extract the following from it: 12345678901234567890123456789012 None of the regexes I've tried have worked. How can I get the value I want from this string?

This will get all the numbers:
var myValue = /\d+/.exec(myString)

mystr.match(/assignment_group=([^\^]+)/)[1]; //=> "12345678901234567890123456789012"
This will find everything from the end of "assignment_group=" up to the next caret ^ symbol.

Try something like this:
/\^assignment_group=(\d*)\^/
This will get the number for assignment_group.
var str = 'approval=not requested^assignment_group=12345678901234567890123456789012^category=Test^contact_type=phone^',
regex = /\^assignment_group=(\d*)\^/,
matches = str.match(regex),
id = matches !== null ? matches[1] : '';
console.log(id);

If there is no chance of there being numbers anywhere but when you need them, you could just do:
\d+
the \d matches digits, and the + says "match any number of whatever this follows"

Help with a regular expression to capture numbers

I need to capture the price out of the following string:
Price: 30.
I need the 30 here, so I figured I'd use the following regex:
([0-9]+)$
This works in Rubular, but it returns null when I try it in my javascript.
console.log(values[1]);
// Price: 100
var price = values[1].match('/([0-9]+)$/g');
// null
Any ideas? Thanks in advance

Try this:
var price = values[1].match(/([0-9]+)$/g);
JavaScript supports RegExp literals, you don't need quotes and delimiters.
.match(/\d+$/) should behave the same, by the way.
See also: MDN - Creating a Regular Expression
Keep in mind there are simpler ways of getting this data. For example:
var tokens = values[1].split(': ');
var price = tokens[1];
You can also split by a single space, and probably want to add some validation.

Why don't you use this?
var matches = a.match(/\d+/);
then you can consume the first element (or last)
my suggestion is to avoid using $ in the end because there might be a space in the end.

This also works:
var price = values[1].match('([0-9]+)$');

It appears that you escaped the open-perens and therefore the regex is looking for "(90".

You don't need to put quotes around the regular expression in JavaScript.