in reply to How to match a ;

You also need to make sure that $line is clean of final new lines whitespace, otherwise your regex won't match your line because $line will end in a new line whitespace instead of ';' - see http://perldoc.perl.org/functions/chomp.html. Also you might consider /^;\s*$/ to strip trailing whitespace.

Syntax wise, your regex is fine.

Best, beth

Update:Correction (see jwkrahn and Grandfather below).

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Re^2: How to match a ;
by GrandFather (Saint) on Feb 08, 2009 at 09:06 UTC

    Actually no. $ matches an end of line, which may be a \n character. Consider:

    my $line = ";\n";

print $line =~ /$_/ ? "" : "no ", "match: $_\n" for '^;$', '^;', "^;\\
+z";

    [download]

    Prints:

    match: ^;$
match: ^;
no match: ^;\z

    [download]

    Note that \z matches the physical end of the string.

    Perl's payment curve coincides with its learning curve.
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      The  $ regex metacharacter will "[m]atch the end of the line (or before newline at the end)" (emphasis added, perlre section Regular Expressions).

      In the presence of the /m regex modifier, the behavior of  $ is enhanced.

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      I stand corrected, but it was actually '.' and '$' new line behavior I was confusing. I once spent a great deal of time beating my brains out until I figured out that '.' doesn't match \n unless you use the 's' modifier, e.g. /;./s. But the more I think about it, I also am finding '$' less clearer than I thought, but I'll save those questions for another thread.

      Best, beth

      Update 2: removed update 1, appears I still have '$' questions and will need to go to SOPW

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      I'm puzzled as to why you switched to double quotes and then had to escape the backslash in your third pattern. Sticking to single quotes or using qw{ ... } would have obviated that need.

      $ perl -le '
> $line = qq{;\n};
> print
>    $line =~ m{$_}
>    ? q{}
>    : q{no },
>    qq{match $_}
>    for q{^;$}, q{^;}, q{^;\z};'
match ^;$
match ^;
no match ^;\z
$ perl -le '
$line = qq{;\n};
print
   $line =~ m{$_}
   ? q{}
   : q{no },
   qq{match $_}
   for qw{ ^;$ ^; ^;\z };'
match ^;$
match ^;
no match ^;\z
$

      [download]

      Cheers,

      JohnGG

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        In some places I like DWIM, in other contexts I like to be explicit. In this case I thought being explicit about how the \ gets handled was probably a good thing™.

        Perl's payment curve coincides with its learning curve.
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Re^2: How to match a ;
by jwkrahn (Abbot) on Feb 08, 2009 at 08:58 UTC

    The $ anchor will match the end of the line with or without a newline at the end so /^;$/ will match both ";" and ";\n".

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