igelkott has asked for the wisdom of the Perl Monks concerning the following question:
Is it possible to use a variable in place of the expression or block of grep? Am I missing something simple or is this simply illegal?
With the simple fragment below, I would like to get a result of 1,2 for both greps but I get all elements on the second. Btw, I get the same results from the expression version: "grep $var, @arr".
use strict; use warnings; my @arr = (1, 2, 3, 4, 5); my $pat = '$_ < 3'; my @res; @res = grep {$_ < 3} @arr; print "Literal:\t@res\n"; @res = grep {$pat} @arr; print "Variable:\t@res\n";
Of course, this is just a test script. The real thing builds the grep pattern in several steps and searches a two-dimensional array. I could do all this differently but the most obvious alternative would be a long list of if statements.
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Replies are listed 'Best First'. | |
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Re: grep { $var } @arr
by Athanasius (Archbishop) on Jul 17, 2014 at 14:56 UTC | |
Re: grep { $var } @arr
by toolic (Bishop) on Jul 17, 2014 at 14:53 UTC | |
by igelkott (Priest) on Jul 17, 2014 at 15:02 UTC | |
Re: grep { $var } @arr
by LanX (Saint) on Jul 17, 2014 at 14:58 UTC | |
Re: grep { $var } @arr
by Anonymous Monk on Jul 17, 2014 at 14:58 UTC | |
Re: grep { $var } @arr
by bulrush (Scribe) on Jul 17, 2014 at 16:53 UTC | |
by Laurent_R (Canon) on Jul 17, 2014 at 18:55 UTC | |
by AppleFritter (Vicar) on Jul 21, 2014 at 09:54 UTC | |
by Laurent_R (Canon) on Jul 21, 2014 at 17:37 UTC | |
by igelkott (Priest) on Jul 21, 2014 at 07:10 UTC |
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