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Regex pattern to find directories only with digits

by Bindo (Acolyte)
on Apr 11, 2013 at 09:55 UTC ( [id://1028109]=perlquestion: print w/replies, xml ) Need Help??

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

Greetings good people! I just want to find all the directories containig only numbers and assign them to an array. For an instance I would want isolate the directories in a certain partition with this format "20130411". Not "2013.kjh" or "NN.201304", or "2013mmkk04". Following is what I tried but they returns not only what i want but the ones with letters

my @LOGDIR = <*>; foreach my $DIR(@LOGDIR) { if($DIR =~ m/([\d])/){ print "$DIR\n"; } }

Please can someone help. Many thanks in advance.


Replies are listed 'Best First'.
Re: Regex pattern to find directories only with digits
by hdb (Monsignor) on Apr 11, 2013 at 10:01 UTC

    This will also find files with names consisting of digits only...

    use strict; my @LOGDIR = <*>; foreach my $DIR(@LOGDIR) { if($DIR =~ m/^(\d+)$/){ print "$DIR\n"; } }

      Thank you very much sir this is exactly what I was looking for. :)

Re: Regex pattern to find directories only with digits
by reisinge (Hermit) on Apr 11, 2013 at 11:32 UTC

    In case you need to search recursively, you may use the File::Find core module:

    use strict; use warnings; use File::Find; # Search current dir unless dir(s) given as command line args @ARGV = qw(.) unless @ARGV; find( \&get_dirs_with_numbers, @ARGV ); sub get_dirs_with_numbers { return unless /^\d+$/; # your regex print $File::Find::name . "\n"; }

    find function from File::Find scans directories in @ARGV recursively and for each file calls the referenced function (coderef) get_dirs_with_numbers. Before calling your function find by default changes to the directory being scanned and sets the following variables:

    • $File::Find::dir -- visited directory path relative to the starting directory
    • $_ -- basename of the file being visited
    • $File::Find::name -- full path of the file being visited

    Well done is better than well said. -- Benjamin Franklin

Re: Regex pattern to find directories only with digits
by Krambambuli (Curate) on Apr 11, 2013 at 10:23 UTC
    with this format "20130411". Not "2013.kjh" or "NN.201304", or "2013mmkk04".

    You might need to refine your definition of 'this format'. Must it be a valid date ? Can it be in the future ? Can it be anywhere in the past ? Could it be less than 8 digits ? ... Etc. If you'd want _precisely_ 8 digits and wouldn't care about validness of the date,

    m/^[\d]{8}$/ might be the regex you want,



      Thank you for your thoughts Mr K. Well I just want to find any directory whos names are only made up of digits. It could either be a date, or even just a of a one digit. like 2. Thank you for clarifying doubts so sooner. :)

Re: Regex pattern to find directories only with digits
by tobias_hofer (Friar) on Apr 11, 2013 at 10:26 UTC


    I also recommend that you specify your regex as close to what you expect as possible. Just taking the "Class" for decimal is opening a wide range of possible matches. You may can start by defining how many digits you expect - mean to say giving your regex a Range. ;-)


Re: Regex pattern to find directories only with digits
by graff (Chancellor) on Apr 12, 2013 at 03:03 UTC
    If I were trying to get just the entries in my current working directory whose names consist entirely of digits, I'd do it like this:
    my @digit_dirs = grep /^\d+$/, <*>; print join( "\n", @digit_dirs, "" );
    If the entries of interest were in fact all "yyyymmdd" digit strings, I'd replace the "+" in the grep regex with {8}.

      Thank you very much good people. I totally understood the concept. You all are the best. By the way if I get a satisfactory answer to a thread that I have started is there a way of closing/locking it? Cos I receive lot of reminders from root saying that I'd have to reply ...etc. Im just a beginner gentlemen so please let me know if there are any rules that I should follow. thanks

        If you are on unix or similar shell, use:
        ls|grep -P "^.*\d{8}.*"
        -P in grep is for using perl regex within shell grep.

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