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

How to make sure that if $mk doesnot match to anyone of @folders,then only push to an array 

#!/usr/bin/perl -w 
use strict;  
use warnings;
my @folders=("inc","Inc","iNc","incr","src","Src");
my $mk = "./media/common/max/tail/common.mk:    $(PROJECT_ROOT)/../../
+Utils/inC";
my $folder_match;
my @folder_match;
foreach $folder_match(@folders)
{

   if($mk !~ /^\/\Q$folder_match\E$/i)# if $mk doesnot match to anyone
+ of @folders,then only push
   {
   push @folder_match ,$mk;
   }
}
print "@folder_match\n";

[download]

Replies are listed 'Best First'.
Re: Pushing to an array
by kennethk (Abbot) on Mar 23, 2011 at 20:21 UTC
    This simplest change you could make to your code to achieve your goal would be to add a flag: 

    my $found = 0;
foreach $folder_match(@folders)
{
    if($mk =~ /^\/\Q$folder_match\E$/i) {# if $mk doesnot match to any
+one of @folders,then only push
        $found = 1;
    }
}
if (not $found) {
    push @folder_match ,$mk;
}

    [download]

    If I were given this task, I would use grep instead, though you could also accomplish this with help from List::MoreUtils.

[reply]
[d/l]

      For both the below inputs $found is "0",any idea why?Ideally for "inc" $found should match

      $mk =./media/common/max/tail/common.mk: $(PROJECT_ROOT)/../../Utils/inc -->$found should be 1

      $mk= ./media/common/max/tail/common.mk: $(PROJECT_ROOT)/../../Utils/inC -->$found should be 0 

      #!/usr/bin/perl -w 
use strict;  
use warnings;
my @folders=("inc","Inc","iNc","incr","src","Src");
my $mk = "./media/common/max/tail/common.mk:    $(PROJECT_ROOT)/../../
+Utils/inc";
my $folder_match;
my @folder_match;
my $found = 0;
foreach $folder_match(@folders)
{
    if($mk =~ /^\/\Q$folder_match\E$/i)
        {# if $mk doesnot match to any+one of @folders,then only push
        $found = 1;
      }
}
print "\nFOUND:$found\n";
if (not $found) {
    push @folder_match ,$mk;
}
print "@folder_match\n";

      [download]
[reply]
[d/l]
        You issue is that $mk does not contain the string ./media/common/max/tail/common.mk:    $(PROJECT_ROOT)/../../Utils/inc as you expect. Variables interpolate in double quotes (see Quote and Quote like Operators), so you are interpolating the special variable $( in your string. You can resolve your issue by either escaping the $ character with a back slash

        my $mk = "./media/common/max/tail/common.mk:    \$(PROJECT_ROOT)/../../Utils/inc";

        or you can swap to string delimiters that do not interpolate, like single quotes

        my $mk = './media/common/max/tail/common.mk:    $(PROJECT_ROOT)/../../Utils/inc';

[reply]
[d/l]
[select]
Re: Pushing to an array
by wind (Priest) on Mar 23, 2011 at 20:29 UTC
    Turn the list of folders into a single regex, then do your test. Add boundary conditions to the regex as required. 
    #!/usr/bin/perl -w 
use strict;  
use warnings;

my @folders = qw(inc Inc iNc incr src Src);
my $folders_re = join '|', map {quotemeta} @folders;

my $mk = "./media/common/max/tail/common.mk:    $(PROJECT_ROOT)/../../
+Utils/inC";

my @folder_match;

if ($mk !~ /$folders_re/i) {
    push @folder_match ,$mk;
}

print "@folder_match\n";

    [download]
[reply]
[d/l]
Re: Pushing to an array
by locked_user sundialsvc4 (Abbot) on Mar 23, 2011 at 20:38 UTC

    I would quite frankly suggest that you look for the simplest possible way to do this ... do it ... and then be done with it.   Unless you have a truly extraordinary amount of data (in which case you probably would be using an SQL table anyway), “the quickest and easiest (for you, for now) way to do” such a task, is the way to do it.   Simply make the intention of the code well-documented and clear, and test it thoroughly.

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