regular expression

toastyman · 17 Jun 2009 at 11:22

Hi all,

I've got a simple regular expression in JavaScript but I can't get it working. I'm simply trying to search a string for words that match a certain format, and then replace them with a bit of code.

For example, it'd search this string..

Code:

The :fox jumped over the :gate into the field

and replace it with

Code:

The "+$('fox').val()+" jumped over the "+$('gate').val()+" into the field

All I have for the regular expression so far is ":[a-zA-Z] ", and that doesn't seem to work. If anyone could give me some pointers it'd be appreciated..

Inquisitor · 17 Jun 2009 at 11:30

You need to quantify your character class with a +, which tells it to take as many matches for the preceding group as possible. You can also omit the capitals in your character class by putting the i modifier on the end of the expression, which tells it to ignore case. Try this:

Code:

/:[a-z]+/i

toastyman · 17 Jun 2009 at 11:39

Fantastic, thanks! I've just tried using that reg expr and it does seem to work, but it only seems to replace the first match...

Code:

var str = 'The :fox jumped over the :gate into the field';
var re = new RegExp(/:[a-z]+/i);
var m = str.replace(re,'cow');
alert(m); //outputs 'The cow jumped over the :gate into the field'

Inquisitor · 17 Jun 2009 at 11:49

Ah, of course, you need the g modifier in there to make it replace all instances; my bad

Code:

'The :fox jumped over the :gate into the field'.replace(/:[a-z]+/gi, 'cow');

toastyman · 17 Jun 2009 at 12:22

Almost there!

Code:

var str = 'The :fox jumped over the :gate into the field';
var re = new RegExp(/:[a-z]+/ig);
var m = str.replace(re,"'+ $('#$&').val()+'");
alert(m);

I just need to work out how to remove the : from the output.. in PHP I would have used preg_replace_callback to remove the colon, but there doesn't seem to be this sort of functionality in javascript..

Dj_Jestar · 17 Jun 2009 at 12:23

and probably the m modifier if parsing paragraphs and not just single lines.

also this pattern should work:

Code:

/(:\w)+/igm

toastyman · 17 Jun 2009 at 12:43

Dj_Jestar said:
and probably the m modifier if parsing paragraphs and not just single lines.

also this pattern should work:

Code:

/(:\w)+/igm

Hi there,

Unfortunately all that seems to do is take the first letter of each match.. f, g etc..

Dj_Jestar · 17 Jun 2009 at 12:49

try without the group..

Code:

/:\w+/igm

toastyman · 17 Jun 2009 at 12:57

Sorted

Code:

var str = 'The :fox jumped over the :gate into the field';
var re = new RegExp(/:\w+/igm);
var m = str.replace(re,function(mo,key,value) {
return "'+$('#"+mo.substr(1)+"').val()+'"
});
alert(m);

Cheers guys!