Regex search substring

Question

I have a question on how to search for a substring using Regexp.

Say, I have a "base" string, such as:
image height=X width=Y end

Both height and width in the above "base" string are assigned integer values that vary, i.e.:
image height=15 width=20 end
image height=10 width=10 end
image height=20 width=5 end

So my question is whether it's possible to fetch width value using canonical regex given that the first part of the substring effectively changes?

given that the first part of the substring effectively changes <- could you explain what you mean by that? — Caridorc
– Caridorc, Commented Sep 30, 2015 at 19:34
I'm not sure about the purpose. What are you trying to do with it? — manonthemat
– manonthemat, Commented Sep 30, 2015 at 19:36

Ori Drori · Accepted Answer · 2015-09-30 20:14:48Z

5

This regexp /width=(\d+)/ should do it:

var strs = ['image height=15 width=20 end this is another width=123', 'width=200 and image height=10 width=10 end', 'image height=20 width=5 end'];

var widths = strs.map(function(str) {
   var matches = str.match(/\bimage height=\d+ width=(\d+) end\b/);
   return matches && matches.length > 1 ? parseInt(matches[1], 10) : null;
});

document.write(widths);

edited Sep 30, 2015 at 20:14

answered Sep 30, 2015 at 19:37

Ori Drori

196k32 gold badges243 silver badges233 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Barmar Over a year ago

You should put \b before width, so it doesn't match something like contentwidth=123

Alex Over a year ago

Thanks, but is there a way to actually have this follow the exact "base" string format? Assuming "width" is present elsewhere in the source text, this would return all such values, whereas I only need those between the "image height=15 width=" and "end".

Ori Drori Over a year ago

Indeed - see edit. I've added to the example strings width=* before and after respectively.

Schlaus · Accepted Answer · 2015-09-30 20:13:26Z

0

The answer by Ori Drori is correct if you don't require the exact form you specified. If you do, you could use this:

var strs = ['image height=15 width=20 end', 'image height=10 width=10 end', 'image height=20 width=5 end'];

var widths = strs.map(function(str) {
   var matches = str.match(/image\ height=\d+\ width=(\d+)\ end/);

   return matches.length > 1 ? parseInt(matches[1], 10) : null;
});

document.write(widths);

edited Sep 30, 2015 at 20:13

answered Sep 30, 2015 at 19:40

Schlaus

19.4k11 gold badges40 silver badges69 bronze badges

2 Comments

Alex Over a year ago

Thanks, but your code returns parameters for "height" and not "width". Can you correct that, please?

Schlaus Over a year ago

@Alex Ah yeah, it actually gets both but I forgot to mention that. I'll fix the answer.

Collectives™ on Stack Overflow

Regex search substring

2 Answers 2

3 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related