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

I'm new to this forum.

This is my first post!

I have an issue what I am trying to get a list of filenames and filter out some filenames.

For instance in a subdirectory "temp" I have the following file names:

hello.pl
hTllo.pl
hVllo.pl
hQllo.pl

[download]

I want to retrieve a list of file names but not include filenames with the second character of 'T' or 'V'.

In other words I want the file names:

hello.pl
hQllo.pl

[download]

The code I've written is:

########################################################

#!/usr/bin/perl -w
my @{Files};
my ${FileName}      = "h[[^TV]]*.pl";
my ${f}             = "";

@Files  = <temp\${FileName}>;

printf ("\n##############[ ${FileName} ]####################\n");
foreach ${f} (@Files)
  { printf("${f}\n");

  }
printf ("##################################\n");

########################################################

[download]

The response I get is:

##############[ h[[^TV]]*.pl ]####################
temp\hTello.pl
temp\hVello.pl
##################################

[download]

The references tell me the '^' character is a NOT and should filter out the T and V characters... but does not.

Any suggestions?

20070320 Janitored by Corion: Added formatting, code tags, as per Writeup Formatting Tips

Replies are listed 'Best First'.
Re: File name filtering with ^ ?
by cdarke (Prior) on Mar 19, 2007 at 22:14 UTC
    I can understand your confusion. Filename wilcards, or glob constructs, use a simpler and DIFFERENT set of meta-characters from Regular Expressions (REs). In REs ^ means 'not' inside [...], but in globbing we use !, so you need [!TV].
    You might also like to consider using the glob function instead of <>, particularly when using patterns from variables. <> are also used for reading files, and the code can get confusing. If you have filenamess with embedded spaces also look at module File::Glob. Update: corrected typos
[reply]
Re: File name filtering with ^ ?
by Anno (Deacon) on Mar 19, 2007 at 22:10 UTC
    You're using regeular expression syntax in a glob. While character classes work in globs much like they do in regular expressions, the negation trhrough "^" is not supported.

    Anno

[reply]
[d/l]
Re: File name filtering with ^ ?
by Bro. Doug (Monk) on Mar 19, 2007 at 22:19 UTC
    Rory.

    Thanks for posting :)

    ^ signifies the beginning unless you're inside of square brackets, in which case (as cdarke pointed out) it means 'not'.

    What you're probably looking for is something like: 
    my @files = () ;
opendir DIR, '/path/to/dir' ;
foreach( readdir DIR ){ 
 # do this unless it matches a digit or char followed by T 
 #  or V followed by anything.
 push @files, $_ unless/[\d\w][TV].*/ ;
}

    [download]
    Bro. Doug :wq
[reply]
[d/l]
      [\d\w] is the same as \w, and adding an anchor to the regex pattern might be more efficient:

   push @files, $_ if /^\w[^TV]/; 

or simply:

   my @files = grep {/^\w[^TV]/} glob("*.pl");

or try shell to negate the character-class:

   my @files = glob("h[!TV]*.pl");

Regards, 
Xicheng
[reply]

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