Re: Ignore a range of numbers ina List

[tybalt89]

#!/usr/bin/perl

# http://perlmonks.org/?node_id=1193467

use strict;
use warnings;

my $aref = [1, 6, 2, 2, 7, 1, 6, 99, 99, 7];
my @copy;

$_ == 6 .. $_ == 7 or push @copy, $_ for @$aref;

use Data::Dumper;
print Dumper \@copy;

[AnomalousMonk]

c:\@Work\Perl\monks>perl -wMstrict -MData::Dump -le
"my $aref = [ 6, 7, 1, 6, 8, 9, 7, 2, 6, 98, 99, 7, 3, 7, 4, 6, 5, ];
 dd $aref;
 ;;
 my @copy;
 $_ == 6 .. $_ == 7 or push @copy, $_ for @$aref;
 ;;
 dd \@copy;
"
[6, 7, 1, 6, 8, 9, 7, 2, 6, 98, 99, 7, 3, 7, 4, 6, 5]

[1, 2, 3, 7, 4]

What's supposed to happen if a "start" code for an exclusion sequence is seen, but no corresponding "stop" code is ever seen? My assumption was that no exclusion would happen. I expected
    [6, 7, 1, 6, 8, 9, 7, 2, 6, 98, 99, 7, 3, 7, 4, 6, 5]
to yield
    [1, 2, 3, 7, 4, 6, 5]

[CountZero]

Building upon your very elegant solution, but changing it somewhat so it now adds to the valid output a sequence at the end that starts with a 6 but never gets ended by a 7.

use Modern::PBP::Perl;

my $aref = [1, 6, 2, 2, 7, 1, 6, 99, 99, 7, 1, 2, 6, 9, 8, 6, 5];
my @copy;
my @stack;

(($_ == 6 .. $_ == 7) and push @stack, $_) or (push @copy, $_ and @sta
+ck=()) for @$aref;
push @copy, @stack;

use Data::Dumper;
print Dumper \@copy;

[AnomalousMonk]

... your ... solution ...

Not mine (unfortunately), but tybalt89's here :)

[shmem]

What's supposed to happen if a "start" code for an exclusion sequence is seen, but no corresponding "stop" code is ever seen?

If the RHS of the flip-flop operator never gets true, then the flip-flop just stays as it is. Hence after 7,4 the 6 turns the flip-flop on, and 6,5 aren't pushed onto @copy.

[AnomalousMonk]

Hence after 7,4 the 6 turns the flip-flop on, and 6,5 aren't pushed onto @copy.

I understand that, but what I was confused about was whether pr33 wanted the 6, 5 to appear in the output or not. pr33 seems to have answered this and related questions here. (At last! A quasi-test-based response :)