in reply to Another Pattern Matching Question

G'day surib,

Welcome to the monastery.

You show the original pattern as: /3B41|2RT\.\d{10}\.\d+\.bin/. Making allowances for the lack of <code> tags, I've assumed 1|2 should be [0|1|2] - this gives a regex which matches the first filename. However, making the same assumption a few lines further down, /3B4[0|1|2]RT\.\d{10}\.\d+R?\.bin/ should have matched both filenames. Was my assumption wrong? Have you shown the correct filenames? Did you type some other part of the regex incorrectly? Please clarify.

-- Ken

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Re^2: Another Pattern Matching Question
by surib (Initiate) on Oct 12, 2012 at 17:25 UTC
    Sorry about not using the 
    .

Here's my code when I actually hard code the '7R', yet it still fails.
+  I must be missing something else? <br>


<code> my ($product, $year, $month, $day, $hour, $suffix, $ver ) = spl
+it /\./, $fileName;

# test file name--naming convention is '<product>.<year>.<month>.<day>
+.<hour>.bin' 

if ($fileName =~ /3B4[0|1|2]RT\.\d{10}\.\7R\.bin/) { 
   ($product, $year, $month, $day, $hour, $ver) = 
      ($fileName =~ /(3B4.RT)\.(\d{4})(\d\d)(\d\d)(\d\d)\.(7R\)\.bin/)
+;
      $version = sprintf "%03d", $ver; # a little confusing, $version 
+is global
                                       # $ver is local
}
elsif ($fileName =~ /3B4\dRT\.\d\d\d\d\.\d\d\.\d\d.\d\dz\.bin/) {
    ($product, $year, $month, $day, $hour, $suffix) = split /\./, $fil
+eName;
}
else {
    print STDERR "($0,$$) ERROR:  invalid file name--'$fileName'\n" if
+ $opt_v;
    exit 2;
}

    [download]
[reply]
[d/l]

      Your solution which adds R? to the original regex was on the right track and achieves what you want, albeit poorly: 

      $ perl -Mstrict -Mwarnings -E 'my $fileName;
my $re = qr{3B4[0|1|2]RT\.\d{10}\.\d+R?\.bin};
$fileName = "3B40RT.2000033121.7.bin.gz";
say +($fileName =~ /$re/) ? "match" : "no match";
$fileName = "3B40RT.2000033121.7R.bin.gz";
say +($fileName =~ /$re/) ? "match" : "no match";
'
match
match

      [download]

      I don't think you understand character classes or alternation (perhaps both). Where you're trying to match a 0, 1 or 2 in the same position, [0-2] would be far better than [0|1|2] (which is trying to match a 0, pipe, 1, pipe or 2 in the same position) - the 2nd pipe is redundant and the 1st pipe isn't wanted anyway. So, here's an improved version: 

      $ perl -Mstrict -Mwarnings -E 'my $fileName;
my $re = qr{3B4[0-2]RT\.\d{10}\.\d+R?\.bin};
$fileName = "3B40RT.2000033121.7.bin.gz";
say +($fileName =~ /$re/) ? "match" : "no match";
$fileName = "3B40RT.2000033121.7R.bin.gz";
say +($fileName =~ /$re/) ? "match" : "no match";
'
match
match

      [download]

      Recommended reading:

      -- Ken

[reply]
[d/l]
[select]
      Or like this: (I've tried so many combinations I'm confusing myself!) 
      if ($fileName =~ /3B4[0|1|2]RT\.\d{10}\.7R.bin/) {
   ($product, $year, $month, $day, $hour, $ver) =
      ($fileName =~ /(3B4.RT)\.(\d{4})(\d\d)(\d\d)(\d\d)\.(7R)\.bin/);
      $version = sprintf "%03d", $ver; # a little confusing, $version 
+is global
                                       # $ver is local

      [download]
[reply]
[d/l]
        If you just want to match 0,1, or 2 and not "|", then your character class should be [012], not [0|1|2].
[reply]
[d/l]
[select]

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