'Space remover using js '.replace(/\s/g, '');

[w3schoon]

Nice to be with you everyone! I want to remove spaces using JavaScript and I found this in the web, var a=" W 3 S c h o o l s ";a.replace(/\s/g, ''); output: W3schools I learned that, replace(); - method searches a string for a specified value... http://www.w3schools.com/jsref/jsref_replace.asp \s - Find a whitespace character... http://www.w3schools.com/jsref/jsref_obj_regexp.asp /g - Perform a global match... http://www.w3schools.com/jsref/jsref_obj_regexp.asp '' - Empty string My question is, what is the purpose of "/" before \s? Thank you.

[callumacrae]

Regular expressions have the following syntax:

/expression/flags

The two forwards slashes (/) are what makes it a regular expression, just like strings have quotes around them. The expression is the regular expression itself, and the flags are stuff like telling the regular expression to be global ("g" is the modifier, not "/g"). I would recommend disregarding the w3schools regex ref you linked to, it isn't very good.

Edited February 9, 2013 by callumacrae

[w3schoon]

@callumacrae: Thanks a lot for the info. But why did you said,

I would recommend disregarding the w3schools regex ref you linked to, it isn't very good.

? Can you give me very good link about regex?

[Don E]

This is a pretty good link: http://www.regular-expressions.info/

[callumacrae]

This is a pretty good link: http://www.regular-expressions.info/

Yep, this is a very good tutorial by the author of "Regular Expressions Cookbook". If you want to know literally everything about regular expressions, buy Mastering Regular Expressions. It will make your head hurt, though.

[jeffman]

Mere mortals cannot know everything about regular expressions. That skill belongs to the gods.

[callumacrae]

I once worked with a guy who could write any regular expression without a reference. I learned from him to always understate your regex abilities, or you will spend half your time writing regular expressions.

[w3schoon]

Thanks a lot guys! I learned many things and I will start studying Regular Expressions!

[thescientist]

fwiw, the power of regex comes in finding patterns in strings. for a simple substitution method like in the OP, a regex might be considered excessive overhead.

[callumacrae]

fwiw, the power of regex comes in finding patterns in strings. for a simple substitution method like in the OP, a regex might be considered excessive overhead.

The equivalent string operation would be pretty inefficient, though.

[Ingolme]

The equivalent string operation would be pretty inefficient, though.

You mean this?

a.split(" ").join("");

Benchmarking. 1,000,000 iterations:

Split method: 1210msRegExp method: 1504ms

[callumacrae]

Oh, didnt read the original post properly (thought the OP wanted to remove duplicate spaces). Why don't you use .replace?