regex for numbers

BernieC has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: regex for numbers by choroba (Cardinal) on Apr 07, 2021 at 15:50 UTC
See `looks_like_number` in Scalar::Util. `map{substr$_->[0],$_->[1]\|\|0,1}[\\|\|{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^ARGV,3]`	[reply] [d/l] [select]
Re: regex for numbers by haukex (Archbishop) on Apr 07, 2021 at 15:49 UTC
Regexp::Common::number	[reply]
Re: regex for numbers by hippo (Archbishop) on Apr 07, 2021 at 16:11 UTC
It's an FAQ! There's also a Q&A entry here: How to identify a number datatype in a string? 🦛	[reply]
Re: regex for numbers by BernieC (Pilgrim) on Apr 07, 2021 at 17:00 UTC
Thanks for all the obvious things I missed [but seeing the regexes that do the job, I can see why it was tricky to do it by starting with "\d+" Odd - I guessed there was a module that'd do it, and I searched CPAN for "number" and it delivered a lot of modules and the Regexp module didn't show up {what mostly showed up were modules for messing with international phone numbers. :o)} Doesn't matter I guess THANKS ALL!!	[reply]
Re: regex for numbers by hrcerq (Monk) on Apr 07, 2021 at 21:18 UTC
This comment might be a bit late, but anyway... coincidentally, I read yesterday an example in perlretut, which addresses precisely this question. The final solution is the same as presented in the FAQ, by the way.	[reply]
Re: regex for numbers by Discipulus (Canon) on Apr 07, 2021 at 17:30 UTC
Hello BernieC, you got obvious and wise answers; I'm not here for this :) What about `{ local $@; eval 0 + $maybe_a_number ... }`? L* There are no rules, there are no thumbs.. Reinvent the wheel, then learn The Wheel; may be one day you reinvent one of THE WHEELS.	[reply] [d/l]
Re^2: regex for numbers by choroba (Cardinal) on Apr 07, 2021 at 18:59 UTC
Perl happily accepts `0 + '1.1.'` (well, it warns, but it doesn't throw an exception). So, eval alone isn't enough. `map{substr$_->[0],$_->[1]\|\|0,1}[\\|\|{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^ARGV,3]`	[reply] [d/l] [select]
Re^3: regex for numbers by haukex (Archbishop) on Apr 07, 2021 at 19:12 UTC
So, eval alone isn't enough. ... and if the idea was to capture the `numeric` warnings, then Scalar::Util's `looks_like_number` provides the same functionality.	[reply] [d/l] [select]