only want numerics in field

newby2perl has asked for the wisdom of the Perl Monks concerning the following question:

Replies are listed 'Best First'.
Re: only want numerics in field by davido (Cardinal) on Apr 21, 2014 at 16:37 UTC
You could use Regexp::Common's "number" extension to detect reals, which is what you seem to be seeking: `if( $string =~ /^$RE{num}{real}$/ ) { print "Match!\n"; } else { print "Reject!\n"; }` [download] You don't want to invent this yourself. Just look at the regular expression that `$RE{num}{real}` contains: `perl -MRegexp::Common=number -E 'say $RE{num}{real}' (?:(?i)(?:[-+]?)(?:(?=[.]?[0123456789])(?:[0123456789]*)(?:(?:[.])(?:[ +0123456789]{0,}))?)(?:(?:[E])(?:(?:[-+]?)(?:[0123456789]+))\|))` [download] ...better off using a solution from Regexp::Common, or the `looks_like_number()` utility Limbic~Region suggested, or both. Dave	[reply] [d/l] [select]
Re: only want numerics in field by Limbic~Region (Chancellor) on Apr 21, 2014 at 15:44 UTC
newby2perl, Scalar::Util has a function call looks_like_number(). The only thing is I believe it allows scientific notation which your example doesn't include. Cheers - L~R	[reply]
Re: only want numerics in field by bigj (Monk) on Apr 21, 2014 at 15:52 UTC
Your formatting is pretty much screwed. However, if you want to check a field for content...it should contain only numeric values like 12345.67 or 0 or 0.00 or -123.78, the usual regexp to do that would be like: `/^[+-]\d+(?:\.\d+)?$/ # or if you want either no decimals or exactly 2 decimals /^[+-]\d+(?:\.\d\d)?$/` [download] But I think, if I look to your code, you seem to have more than just a decimal number inside. You might also take a look to modules like Regexp::Common. Most of us will make a mistake here or their when build Regexps, the good thing common things is that we aren't the first one doing them :-) Greetings, Janek Schleicher	[reply] [d/l]
Re^2: only want numerics in field by Limbic~Region (Chancellor) on Apr 21, 2014 at 16:09 UTC
bigj, Your regex will indicate that `.25` is not a number. You also require a leading sign `[+-]`. I realize that defintion of "what is numeric" is sorely lacking by the OP but I wanted to point this out to anyone who may come along later. Cheers - L~R	[reply] [d/l] [select]
Re^3: only want numerics in field by bigj (Monk) on Apr 21, 2014 at 16:37 UTC
Just one more reason to not reinvent the wheel :-) You're of course right. Greetings, Janek Schleicher	[reply]
Re^2: only want numerics in field by newby2perl (Initiate) on Apr 21, 2014 at 16:40 UTC
yes it will be an amount with only 2 places after the decimal.	[reply]
Re^3: only want numerics in field by newby2perl (Initiate) on Apr 21, 2014 at 16:48 UTC
it should allow - for negative numbers	[reply]
Re: only want numerics in field by AnomalousMonk (Archbishop) on Apr 21, 2014 at 19:12 UTC
BTW, a tangential point: The loop `while ( $amount2 =~ / / ){ $amount2 =~ s/ //g; }` [download] conditionally does a substitution to remove all spaces if a space is found in a string. However, `s/ //g` on its own will never do anything if a match is not found. You are essentially doing one match for the price of two. You can profitably lose the loop (but take the substitution).	[reply] [d/l] [select]