On Jul 19, Mooney Christophe-CMOONEY1 said:
>"That's an excellent question," i said to myself; "i'll bet there's a
>module for that!"
>
>So, i looked on cpan, and it looks like Array::Compare will do the
>trick.
All the same, this is a question that stumps a lot of people. There are
two ways to approach this, really -- one way is terribly broken and takes
longer than it needs, and the other is fast and simple.
The first method is to join each array into a single string, and compare
the two. How does that break?
@a = ("a b", "c");
@b = ("a", "b c");
if (join(' ', @a) eq join(' ', @b)) {
print "\@a and \@b are equal!\n";
}
See why that breaks? (If not, run it.) "So," you say, "you just need to
find a unique string!" That requires going through both arrays to find a
string that is not found in ANY element -- that's a LOT of work, and it
requires you to loop over the arrays. Why not COMPARE the elements AS you
loop?
That is method two:
sub compare {
my ($aref, $bref) = @_;
return 0 if @$aref != @$bref; # ensure the same size
$aref->[$_] ne $bref->[$_] and return for 0 .. $#$aref;
return 1;
}
It is called thus:
if (compare(\@this, \@that)) {
# the same
}
The dissection of that for loop is:
for my $idx (0 .. $#$aref) {
if ($aref->[$idx] ne $bref->[$idx]) { return 0 }
}
I hope this helps.
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