Re: compare arrays, and list the difference

[roboticus]

in reply to compare arrays, and list the difference

lza:

You can't have looked very hard for the answer, as it's a commonly-asked question. Read perldoc perlfaq4.

Update: I was probably expecting a bit much in thinking that beginning programmers would be able to adapt the code in perlfaq4 "How do I compute the difference of two arrays? How do I compute the intersection of two arrays". As pennance, here's a simple adaptation:

#!/usr/bin/perl
use 5.14.0;
use warnings;
use autodie;

my @source=(1, 2, 3, 4, 5, 7);
my @target=(0, 1, 3, 4, 6);
my %count = ();

$count{$_} = 1 for @source;
$count{$_} |= 2 for @target;

my (@not_in_src, @not_in_tgt, @in_both);

for (sort keys %count) {
    push @not_in_tgt, $_ if $count{$_} == 1;
    push @not_in_src, $_ if $count{$_} == 2;
    push @in_both,    $_ if $count{$_} == 3;
}

print "Not in source: ", join(", ", @not_in_src), "\n";
print "Not in target: ", join(", ", @not_in_tgt), "\n";
print "In both: ", join(", ", @in_both), "\n";

...roboticus

When your only tool is a hammer, all problems look like your thumb.

[BrowserUk]

Which of FAQ4 answers the OPs question?

[roboticus]

BrowserUk:

It seems that "How do I compute the difference of two arrays? How do I compute the intersection of two arrays?" gives the essential information. Perhaps my expectation that it's a simple step from the FAQ to this question is a bit much?

In any case, since it's not an exact match to the question, I shouldn't have said that it's a FAQ.

...roboticus

When your only tool is a hammer, all problems look like your thumb.

[iza]

it's the faq I was referring to in my question

I didn't know the $count{$_} |= 2 for @target; trick - I like it, thanks !