Javascript replace function using regular expressions

Question

I am trying to use javascript's replace function to replace a string. But it just replaces the first instance. So when I use regular global expressions,

var result = 'moaning|yes you|hello test|mission control|com on'.replace(/|/g, ';');

I get: http://jsfiddle.net/m8UuD/196/

I want to get:

moaning;yes you;hello test;mission control;com on

Denys Séguret · Accepted Answer · 2013-04-05 19:34:46Z

6

Simply escape the pipe :

 'moaning|yes you|hello test|mission control|com on'.replace(/\|/g, ';');

Here you'll find the list of regex special characters that you should generally escape.

answered Apr 5, 2013 at 19:34

Denys Séguret

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Ian Over a year ago

@SamiyaAkhtar Just make sure you Accept the answer when you are able to

Naftali · Accepted Answer · 2013-04-05 19:34:52Z

3

var result = 'moaning|yes you|hello test|mission control|com on'.replace(/\|/g, ';');

edited Apr 5, 2013 at 19:34

Naftali

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answered Apr 5, 2013 at 19:34

Viele

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Blender · Accepted Answer · 2013-04-05 19:36:05Z

2

You could also use .split() and .join():

'moaning|yes you|hello test|mission control|com on'.split('|').join(';')

answered Apr 5, 2013 at 19:36

Blender

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Ian Over a year ago

This is probably a dumb question in this context, but do you know of any "performance issues" between this and replace with a Regex? I know both this and replace will effectively do the same thing, I'm just wondering. Is it "intensive" to split and then join? Especially compared to using a Regex? I'm sure in either case, it's not that important as this is a small string and only executed once, but I just thought I'd ask

Blender Over a year ago

@Ian: split/join seems to be a bit faster, at least on Chrome: jsperf.com/split-join-vs-regex2, but not by much

Ian Over a year ago

Thanks for providing that. I should've just done that myself. Of course on Firefox, I get the opposite results :) I guess I was wondering if you knew of something like "Well, regex gets compiled beforehand, therefore it can execute quicker" or something like that. And I also wonder if there's a relation to the size of the string. For some reason, I feel like split/join isn't as good as the size of the string increases.

Blender Over a year ago

@Ian: Sorry, I don't really know about that. I think there will be a point where creating the array and joining it will take up more time than the regex, but it might take a really long string: jsperf.com/split-join-vs-regex2/2

Schleis · Accepted Answer · 2013-04-05 19:35:46Z

1

You need to escape the '|' like:

var result = 'moaning|yes you|hello test|mission control|com on'.replace(/\|/g, ';');

http://jsfiddle.net/PM4PT/

answered Apr 5, 2013 at 19:35

Schleis

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Comments

6502 · Accepted Answer · 2013-04-05 19:47:13Z

Many characters are reserved because have a special meaning in a regular expression, so to use one of them you need to "escape" it by placing a backslash \ right before the special character. These are:

(   start of a sub-expression
)   end of a sub-expression
{   start of repetition range
}   end of a repetition range
[   start of a character set
]   end of a character set
+   one or more repetitions
*   zero or more repetitions
^   start of string
$   end of string
|   "or" connection between alternatives
\   start of special code or escape
/   start or end of regexp pattern

For example a regular exprerssion to match all open square bracket is /\[/ (note the backslash). If you need to look for a backslash you must but a backslash in front of it (so doubling it).

Unfortunately there is no predefined Javascript function for "escaping" all special characters.

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