Replace only if the containing string length is greater than X

Question

I've a regex that will only match one character of the strings. I want to test the lentgh of its containing string and if it was greater than 4 then make the replacement. For example, the regex is /\d/. I want to use the functional form of replace to match 12345 but not 1234.

Something like:

text.replace(regex, function(match) {
       if (STRING.length > 4)
            return replacement
       else
            return match;
  });

Note: /\d/ is just an example. I didn't mention the real regex to focus on my real question, illustrated above.

for all those like me who didn't know you could pass a function to the replace function: https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/replace — Sebas, Apr 28 '13 at 13:48

score 5 · Accepted Answer · answered Apr 28 '13 at 13:52

5

Or if you want to do it that way:

function replaceWithMinLength (str, minLength) {
   str.replace(/\w+/, function(match) {
      if (match.length > minLength) {
        return match;
      } else {
        return str;
      }
   });
}

answered Apr 28 '13 at 13:52

Chris

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1
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[**This**](http://jsfiddle.net/627rF/1/) is the original, and [**this**](http://jsfiddle.net/627rF/2/) is trying to implementing your code. – Iryn Apr 28 '13 at 17:14
Ok, I see the problem but I dont know what your actual goal is. Can you give the the result or wich characters should be red? – Chris Apr 28 '13 at 18:13
I probabely should have used a better example. Please see [this fiddle](http://jsfiddle.net/627rF/4/). The first line should not have any red character, as the number have less than five digits. – Iryn Apr 28 '13 at 19:02
Also, if more information is needed, see [my previous question](http://stackoverflow.com/questions/16241625/why-this-regex-does-not-work-with-eastern-arabic-numerals). – Iryn Apr 28 '13 at 19:05
Ah, so it would make sense to check the length before applying the regex replace right? http://jsfiddle.net/XpjF2/ – Chris Apr 28 '13 at 19:42
Thanks, but there's still a problem :) [http://jsfiddle.net/XpjF2/2/](http://jsfiddle.net/XpjF2/2/) – Iryn Apr 28 '13 at 19:54
Better illustrated here [http://jsfiddle.net/XpjF2/3/](http://jsfiddle.net/XpjF2/3/). – Iryn Apr 28 '13 at 19:59
1

Ok, now im sure that this must be possible with regex. But with javascript: http://jsfiddle.net/7X7em/1/ – Chris Apr 28 '13 at 20:50
Aslo, can you please tell me what do you think about its performance hit? Is this something to worry about? – Iryn Apr 28 '13 at 21:12
1

Well I do not advise to use this method, but performance will not suffer that much I guess. Think of 3D canvas calculations browser do these days ;) – Chris Apr 28 '13 at 21:53

score 4 · Answer 2 · answered Apr 28 '13 at 13:48

4

You're putting the horse before the cart. You would be better off:

if(string.length > 4) {
  string.replace('needle','replacement');
}

answered Apr 28 '13 at 13:48

oomlaut

763
4
12

That was my first thought, but… I think the OP would just have used `text` in that case. :) – Ry- Apr 28 '13 at 13:50
10

the horse is supposed to be before the cart :) – Smern Apr 28 '13 at 13:50

score 0 · Answer 3 · answered Apr 28 '13 at 13:49

0

So by “containing string”, you mean like the same sequence of digits? Match them all at once:

text.replace(/\d{5,}/g, function(string) {
    return string.replace(/\d/g, function(match) {
        return replacement;
    });
});

For example. The \d{5,} can easily be adapted to any type of string-thing.

answered Apr 28 '13 at 13:49

Ry-

218,210
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@Iryn: In what way? Can you show your code, or a [short example](http://codepen.io/pen)? – Ry- Apr 28 '13 at 15:01
Please see [this question](http://stackoverflow.com/questions/16241625/why-this-regex-does-not-work-with-eastern-arabic-numerals). – Iryn Apr 28 '13 at 15:11
How to it for number. Example : How I would set all number below 40,000 to 0 in a text files *(they are delimited by commas semicolons full dots and spaces )* – user2284570 Jul 16 '15 at 13:23

Replace only if the containing string length is greater than X

3 Answers3