matching between 1 to 8 digits but not more

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

Replies are listed 'Best First'.
Re: matching between 1 to 8 digits but not more by moritz (Cardinal) on Aug 20, 2009 at 09:11 UTC
Note that a string with 9 digits also contains 8 digits. so you'll have to be more careful. A good way to re-formulate the question is: does the string contain 1 to 8 digits that are neither followed nor preceded by digits? When you ask it like that, it's easy to formulate as a regex: `m/(?<! \d ) \d{1,8} (?! \d )/x` [download] For an explanation of the look-ahead and look-behind groups see perlre. Perl 6 projects - links to (nearly) everything that is Perl 6.	[reply] [d/l]
Re: matching between 1 to 8 digits but not more by FunkyMonk (Bishop) on Aug 20, 2009 at 08:57 UTC
`if (m/\d{9,}/) { # more than 8 digits } elseif (m/\d/) { # 8 or less digits else { # no digits }` [download]	[reply] [d/l]
Re: matching between 1 to 8 digits but not more by cdarke (Prior) on Aug 20, 2009 at 09:08 UTC
You need to consider what comes before and after the digits (\D is a non-digit): `use strict; use warnings; while( my $Number = <DATA> ) { chomp $Number; if($Number =~ /(\D\|^)\d{1,8}(\D\|$)/){ print "$Number is OK\n" } else { print "$Number has more than 8 digits!\n" } } __DATA__ 1234567 12345678 123456789 grunge 1234567 grunge grunge 12345678 grunge grunge 123456789 grunge` [download] Gives: `1234567 is OK 12345678 is OK 123456789 has more than 8 digits! grunge 1234567 grunge is OK grunge 12345678 grunge is OK grunge 123456789 grunge has more than 8 digits!` [download]	[reply] [d/l] [select]
Re: matching between 1 to 8 digits but not more by Old_Gray_Bear (Bishop) on Aug 20, 2009 at 09:13 UTC
I think you want to add anchors to your regex -- `if($Number =~ m/^\d{1,8}$/){ $N = $Number; } else { print("line has more than 8 digits!\n"); }` [download] This seems to satisfy the requirement -- '12345678' and '123456' don't print; '12345654321' does. ---- I Go Back to Sleep, Now. OGB	[reply] [d/l]
Re: matching between 1 to 8 digits but not more by james2vegas (Chaplain) on Aug 20, 2009 at 09:01 UTC
`if ($Number =~ m/\d\d{8,}/) { print ("line has more than eight digits!\n"); }` [download] This only really does what your message indicates, i.e. it doesn't test for zero digits.	[reply] [d/l]
Re: matching between 1 to 8 digits but not more by JavaFan (Canon) on Aug 20, 2009 at 10:04 UTC
Assuming you mean you don't want more than 8 digits in a row: `if ($Number =~ /\d{9}/) { print "Line has more than 8 digits!\n" } elsif ($Number =~ /\d/) { $N = $Number; } else { print "Line has no digits at all!\n"; }` [download]	[reply] [d/l]
Re^2: matching between 1 to 8 digits but not more by Anonymous Monk on Aug 21, 2009 at 14:12 UTC
If you don't care about consecutiveness: `$digits = () = 'a1b2c3d4 e5f6g7h8i9' =~ /\d/g;`	[reply] [d/l]
Re: matching between 1 to 8 digits but not more by bpoag (Monk) on Aug 21, 2009 at 22:41 UTC
Your test should be simply: `if ($Number!~/^[0-9]{1,8}$/) { ## blah blah }` [download] ..I'm surprised so many people are having a problem with this. In English: For anything that doesn't explicitly match a string of numbers, and only numbers, of at least 1 character in length, but no more than 8 characters, do ##blah blah. Cheers, Bowie	[reply] [d/l]