Regex expression not working - what am I missing

Question

I am trying to get the number (123) from data written in the format 123:AB.CD.EF.GH.IJ using Javascript.

Currently I have a regular expression /^[0-9]*(?=\:)/ and using

var ABC = pattern.match(regex);

but I keep coming up empty handed. What is wrong with my expression?

What are pattern and regex? Because "123:AB.CD.EF.GH.IJ".match(/^[0-9]*(?=\:)/) works. — Gumbo
– Gumbo, Commented Apr 4, 2011 at 17:20
'123:AB.CD.EF.GH.IJ'.match(/^[0-9]*(?=\:)/) works just fine for me. Your problem must be elsewhere. — Matt Ball
– Matt Ball, Commented Apr 4, 2011 at 17:22
Sorry was very vague, pattern is just the text in the format I gave and regex is that regular expression defined using var regex = RegExp("^[0-9]*(?=\:)", "") — Magic Lasso
– Magic Lasso, Commented Apr 4, 2011 at 17:22

Jakub Hampl · Accepted Answer · 2011-04-04 17:23:10Z

6

Or you could skip regex and use pattern.split(':')[0].

edited Apr 4, 2011 at 17:23

Jakub Hampl

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answered Apr 4, 2011 at 17:22

Niklas Wulff

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4 Comments

andrew Over a year ago

I like this even better. It's good to avoid regexes if not doing complicated text processing.

Magic Lasso Over a year ago

Thanks and good answer. I really didnt want to pass another variable. Cheers out to everybody.

beatgammit Over a year ago

Nice. Sometimes simpler is better.

Niklas Wulff Over a year ago

Thanks! I just really never get regexes, which makes me good at thinking of ways to avoid them...

andrew · Accepted Answer · 2011-04-04 17:21:40Z

0

Try

var number = value.replace(/:.*/);   // where value is the "123:AB.CD.EF.GH.IH" string

Sometimes doing the same thing a different way will yeidl better result, I've found with regexs.

answered Apr 4, 2011 at 17:21

andrew

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Comments

beatgammit · Accepted Answer · 2011-04-04 17:22:43Z

0

Match returns an array. You might need pattern.match(regex)[1] where 1 is the matched string. You don't need the (?=\:) at the end. You will also need to specify what you are capturing.

Try this:

regex = /^([0-9]*)/

The parenthesis say what you want to match. Remember, match returns an array. Use JSON.stringify() to find what you're getting. JSON.stringify(ABC). JSON is supported on FF, Chrome, and Safari I believe.

answered Apr 4, 2011 at 17:22

beatgammit

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