Re: pull out num from str

First of all, a character class already means "one of these characters", so your pipe isn't doing what you think it is. It would match |123. So that should be [+-]. It's also not necessary to escape the plus sign within a character class. Then, to say "zero or one of these," append ? to it, giving you [+-]? . You can also drop the .* from the beginning and .*$ from the end, since they're implied anyway. That gets your regex down to /([+-]?\d+)/ .

Aaron B.
My Woefully Neglected Blog, where I occasionally mention Perl.

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Re^2: pull out num from str by jwkrahn (Abbot) on Apr 23, 2012 at 08:45 UTC
You can also drop the . from the beginning* `"123 456" =~ /([+-]?\d+)/` and `"123 456" =~ /.([+-]?\d+)/` match two different things because `.` at the beginning is greedy.	[reply] [d/l] [select]
Re^2: pull out num from str by icoder (Novice) on Apr 23, 2012 at 09:14 UTC
Thanks . works exactly as expected	[reply]
Re^2: pull out num from str by icoder (Novice) on Apr 23, 2012 at 11:55 UTC
This works fine , Is there any disadvantages of using this regex,because ,others in this thread posted lenthy regexes which will do the same thing. please suggest	[reply]
Re^3: pull out num from str by aaron_baugher (Curate) on Apr 23, 2012 at 17:01 UTC
If it works with all the formats your data includes, that's what's important. As jwkrahn pointed out, by removing your leading `.`, I did change the effect of yours in any case where there is more than one matching number in a string: `$str = 'This sentence has two numbers, +13 and -15.'; $str =~ /([+-]?\d+)/; # matches +13, first match found $str =~ /.([+-]?\d+)/; # matches -15 because .* is greedy` [download] So which of those you use depends on whether you want to find the first number or the last number in a line. If your lines only have one number, it won't matter. Aaron B. My Woefully Neglected Blog, where I occasionally mention Perl.	[reply] [d/l] [select]