On May 10, Tucker, Ernie said:
>Here is my first problem to the list. I have two different files with
>information that I need to find out what both have.
This is answered in the Perl FAQ:
japhy% perldoc -q intersection
Found in /usr/local/lib/perl5/5.00502/pod/perlfaq4.pod
"How do I compute the difference of two arrays? How do I compute the
intersection of two arrays?"
Use a hash. Here's code to do both and more. It assumes that
each element is unique in a given array:
@union = @intersection = @difference = ();
%count = ();
foreach $element (@array1, @array2) { $count{$element}++ }
foreach $element (keys %count) {
push @union, $element;
push @{ $count{$element} > 1 ? \@intersection : \@difference },
$element;
}
This assumes you have two arrays, which you don't, technically. However,
you can make the following adjustments:
open FILE_1, "< this" or die "can't read this: $!";
$seen{$_}++ while <FILE_1>;
close FILE_1;
open FILE_2, "< that" or die "can't read that: $!";
while (<FILE_2>) {
print if $seen{$_};
}
close FILE_2;
This is better than plopping the content of the files into arrays and
using the code from the FAQ.
--
Jeff "japhy" Pinyan [EMAIL PROTECTED] http://www.pobox.com/~japhy/
RPI Acacia brother #734 http://www.perlmonks.org/ http://www.cpan.org/
** Look for "Regular Expressions in Perl" published by Manning, in 2002 **
<stu> what does y/// stand for? <tenderpuss> why, yansliterate of course.
[ I'm looking for programming work. If you like my work, let me know. ]
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