Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:
Hi Monks,
I have a function with should select files by a given list of extension. I wrote a program, which did not work. After playing a little around I found a working solution (using a local variable: my $x). But I do not understand, why my first version is not working.
Can you help me explaining the difference between this two versions:
In the first version the expression(@ext) is replaces by '1';
In the second version the expression(@ext) is correct. ('f.*\\.txt$', 'f.*\\.txt.*$')
Thanks for your help !!!
use strict; use warnings; use Data::Dumper qw(Dumper); $\="\n"; my @ext; my @list=('f1.txt','f2.txtx','f3.xtxt','x1.txt'); my $ex="f*.txt,f*.txt*"; print " Version 1: Not working--------------------------------"; @ext=map { $_=quotemeta($_).'$'; s/\\\*/.*/;} split(/,/,$ex); + # <<<<<< compare this line print "qr=".Dumper(\@ext); foreach my $e(@ext) { foreach my $f(@list) {print "Match: ($e) => $f" if ($f=~m/$e/); }} print " Version 2: working--------------------------------"; @ext=map { my $x=quotemeta($_).'$'; $x=~s/\\\*/.*/g; $_=$x;} split(/,/ +,$ex); # <<<<<< compare this line print "qr=".Dumper(\@ext); foreach my $e(@ext) { foreach my $f(@list) {print "Match: ($e) => $f" if ($f=~m/$e/); }}
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Replies are listed 'Best First'. | |
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Re: Why do I need a local variable in map function
by haukex (Archbishop) on May 23, 2019 at 07:41 UTC | |
by Anonymous Monk on May 23, 2019 at 09:35 UTC |
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