Re: Regex for files

all the files that begin with messages and MAY have a "." and a digit behind it, but it should not match something that has say .txt, .pl, etc.

Having a directory populated with these files

messages
messages.
messages.1
messages1.2.3
messages.1.gz
messages.2
messages.3
messages.pl
messages.txt
[download]

the following code

opendir D, '.';
while(readdir D) {
   /^messages(?:\.\d?)?$/ and print $_,"\n";
}
[download]

will output those:

messages.
messages.2
messages
messages.1
messages.3
[download]

The elements of that regular expression can be best explained using the x modifier (see perlre and perlfunc):

opendir D, '.';
while(readdir D) {
   m/            # begin of match
       ^         # match at the beginning of element, i.e. $_
       messages  # match 'messages' literally
       (         # begin of match group
        ?:       # subject to * ? +  not creating a capture
          \.     # match a period
          \d?    # optionally (?) match a digit
       )         # end of match group
       ?         # which may or not occur
       $         # before the end of the string
    /x           # tell m// that we use extended regex w/comments
    and          # if found
    print "$_\n" # print it out.
}
[download]

perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'

Comment on Re: Regex for files Select or Download Code

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Re^2: Regex for files (path::tiny) by Anonymous Monk on Apr 23, 2015 at 11:00 UTC
readdir is low level :) Path::Tiny is a whole nother level :P `use Path::Tiny qw/ path /; print "$_\n" for path('.')->children( qr /^messages(?:\.\d?)?$/ ) ;` [download]	[reply] [d/l]
Re^3: Regex for files (path::tiny) by shmem (Chancellor) on Apr 23, 2015 at 12:16 UTC
readdir is low level :) Path::Tiny is a whole nother level :P That may well be, but is irrelevant for Regex for files. perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'	[reply] [d/l]
Re^4: Regex for files (path::tiny) by Anonymous Monk on Apr 23, 2015 at 15:38 UTC
readdir is low level :) Path::Tiny is a whole nother level :P That may well be, but is irrelevant for Regex for files. In what way?	[reply]
Re^5: Regex for files (path::tiny) by shmem (Chancellor) on Apr 23, 2015 at 21:09 UTC
Re^6: Regex for files (path::tiny) by Anonymous Monk on Apr 24, 2015 at 00:23 UTC