One of my projects required me to find the
difference between two arrays. I look through
Super Search
popped this node:
RE: Comparing arrays.
UPDATED: Er. work project that is, not homework
project.
A look through the language.perl.org perlfaq4 showed a
snippet of code.
I added some Dumper routines to see what was actually
going on and flushed it out for my
purposes. I thought I'd include it here as it helped me
to better understand the answer in the FAQ but basically
it's the code snippet from the FAQ implememented as
something that made sense to me. ^-^ Maybe it would help
out someone else?
fong
#!/usr/bin/perl -w
#
# Union, Intersection, and Difference between two arrays
#
# 03.15.2001
# A quick little hack based on information contained in
# this node:
# http://perlmonks.org/index.pl?node_id=5733
#
# As an example of testing two array's equality
#
# This is taken directly out of the faq here:
# http://language.perl.com/newdocs/pod/perlfaq4.html#How_do_I_test_whe
+ther_two_arrays
#
#
#
use strict;
use Data::Dumper;
my @a1 = ("CUSTORDS.DAT",
"RECEIPTS.DAT");
print "Array 1:\n";
print Dumper(@a1),"\n";
my @b1 = ("CUSTORDS.DAT",
"ONHAND.DAT",
"RECEIPTS.DAT");
print "Array 2:\n";
print Dumper(@b1),"\n";
my @union = my @inter = my @diff = ();
my %count = ();
foreach my $element (@a1, @b1) {
$count{$element}++;
};
foreach my $element (keys %count) {
push @union, $element;
push @{ $count{$element} > 1 ? \@inter : \@diff }, $element;
};
print "Count:\n";
print Dumper(%count),"\n";
print "Union:\n";
print Dumper(@union),"\n";
print "Intersection:\n";
print Dumper(@inter),"\n";
print "Difference:\n";
print Dumper(@diff),"\n";
Sample Output:
Array 1:
$VAR1 = 'CUSTORDS.DAT';
$VAR2 = 'RECEIPTS.DAT';
Array 2:
$VAR1 = 'CUSTORDS.DAT';
$VAR2 = 'ONHAND.DAT';
$VAR3 = 'RECEIPTS.DAT';
Count:
$VAR1 = 'ONHAND.DAT';
$VAR2 = '1';
$VAR3 = 'RECEIPTS.DAT';
$VAR4 = '2';
$VAR5 = 'CUSTORDS.DAT';
$VAR6 = '2';
Union:
$VAR1 = 'ONHAND.DAT';
$VAR2 = 'RECEIPTS.DAT';
$VAR3 = 'CUSTORDS.DAT';
Intersection:
$VAR1 = 'RECEIPTS.DAT';
$VAR2 = 'CUSTORDS.DAT';
Difference:
$VAR1 = 'ONHAND.DAT';
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