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in reply to Regex \. help

Something using zero width negative look ahead (?!) should work:

my @t = qw( regex regex.1 regex.12 regex.1a regex.a regex.abc regex.a1
+ oregex.2 );
for (@t) {
    print $_;
    print ' matches!' if /^regex(?!\.[^\d])(\.\d*)?/;
    print "\n";
}

[download]
gives: 
regex matches!
regex.1 matches!
regex.12 matches!
regex.1a matches!
regex.a
regex.abc
regex.a1
oregex.2

[download]

Checkout the "Look-Around Assertions" section in the perlre documentation. In the example above, the negative look-ahead says fail if the next characters are a period followed by anything that isn't a digit.

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Re^2: Regex \. help
by AnomalousMonk (Archbishop) on Nov 22, 2014 at 00:47 UTC

    Loops: You read the OP a bit more slowly and carefully, and came closer, I think, to answering codz67's question as a result. But the  (\.\d+)? is redundant for the given inputs and outputs if the negative look-ahead is used. (Had it been needed, it would probably have been better as a  (?:...) non-capturing group.) 

    c:\@Work\Perl>perl -wMstrict -le
"my @t = qw( regex regex.1 regex.12 regex.1a regex.a regex.abc regex.a
+1 oregex.2 );
 for (@t) {
   printf qq{'$_'};
   printf ' matches!' if /^regex(?!\.[^\d])/;
   print '';
   }
"
'regex' matches!
'regex.1' matches!
'regex.12' matches!
'regex.1a' matches!
'regex.a'
'regex.abc'
'regex.a1'
'oregex.2'

    [download]

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      Hi,

      Yeah you're right about that. I confess to removing the non-capturing annotation for simplicity sake. Here's a slightly different version where the \d* isn't redundant:

      my @t = qw( regex regex. regex.1 regex.12 regex.1a regex.a regex.abc r
+egex.a1 oregex.2 );
say s/^regex(?!\.[^\d])(\.\d*)?/|$&|/r for (@t);

      [download]
      |regex|
|regex.|
|regex.1|
|regex.12|
|regex.1|a
regex.a
regex.abc
regex.a1
oregex.2

      [download]
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        #!/usr/bin/perl
@filename = `ls  | grep  "^regex\.[0-9]"`;
print @filename;

    ...

        [download]

        prints regex.1. I need it to print regex and regex.1:

        #!/usr/bin/perl
@filename = `ls  | grep  "^regex\.?[0-9]"`;
print @filename;

        [download]

        Doesnt print anything.

        Shouldnt the ? match the . zero or more times? If so why doesnt it print regex and regex.1 As for the .abc I need that to be excluded when it greps. So regex.abc and regex.xyz wont print.

        Thank you for the help so far, I am still stuck on making this work. I will continue to try to make this work, if anyone could assist further I would be very thankful.

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