Problem in "any"

ravi45722 has asked for the wisdom of the Perl Monks concerning the following question:

I want to print only particular lines. For that I wrote like this. But its writing all the lines.

#!/usr/bin/perl
#
use strict;
use warnings;

use List::MoreUtils qw(any uniq);

my @line_numbers = (1,2,5,6,9,10,18,19,23,24,25,30,31,33);
my $line_number = 0;

foreach my $li (1..35)
{
        if (any {$line_number} @line_numbers)
        {
                print "$line_number :\n";
        }
        $line_number++;
}
[download]

Where am I missing??//

Comment on Problem in "any" Download Code

Replies are listed 'Best First'.
Re: Problem in "any" by poj (Abbot) on Jan 23, 2016 at 13:42 UTC
Where am I missing? You need a criteria any BLOCK LIST Returns a true value if any item in LIST meets the criterion given through BLOCK. Sets $_ for each item in LIST in turn: `if (any {$line_number == $_} @line_numbers){` [download] poj	[reply] [d/l]
Re: Problem in "any" by choroba (Cardinal) on Jan 23, 2016 at 13:46 UTC
In the curly braces after `any`, you must specify a code that returns true or false. `$line_number` returns false only in the first iteration of the loop when it's zero, and stays true afterwards. Moreover, you don't need `$line_number`, you already have the `$li` variable that can serve its purpose: `#!/usr/bin/perl use warnings; use strict; use List::MoreUtils qw{ any }; my @line_numbers = (1, 2, 5, 6, 9, 10, 18, 19, 23, 24, 25, 30, 31, 33) +; for my $line_number (1 .. 35) { if (any { $_ == $line_number } @line_numbers) { print "$line_number :\n"; } }` [download] But for the same output, you can just use `print map "$_ :\n", @line_numbers;` [download] Instead of the for loop. ($q=q:Sq=~/;[c](.)(.)/;chr(-\|\|-\|5+lengthSq)`"S\|oS2"`map{chr \|+ord }map{substrSq`S_+\|`\|}3E\|-\|`7**2-3:)=~y+S\|`+$1,++print+eval$q,q,a, [download]	[reply] [d/l] [select]
Re: Problem in "any" by Anonymous Monk on Jan 23, 2016 at 13:44 UTC
In `any BLOCK LIST`, the thing in the BLOCK needs to be a condition that tests against `$_`, which is set to each item of the LIST, `@line_numbers`, until a match is found. Change it to `{$_==$li}`, I am guessing that's the result you're looking for?	[reply] [d/l] [select]