David Newman wrote:
Greetings. I'm looking to compare two contact lists in csv format, and
then print out "here are the records in in Llist only, in Rlist only,
and what's in common."
I should compare only 3 of the 82 fields in each list. There are
differences in some of the other fields that I should ignore.
If I read in each csv file as an array, List::Compare does a nice job of
comparing all 82 fields as a single array element. But I should only
look at 3 fields, not all 82. (snippet A below)
I can also use List::Compare plus a split function to strip out just the
3 fields I'm comparing. However, the resuling arrays then only have
three fields in each array element. (snippet B below)
How to compare only selected fields in each list, but then present all
fields for any matches?
For one of the lists, you can store the records in a hash where the
first 3 fields of each record is the key, and the complete record is the
value. Something like:
my (%Llist, @Rlist, @common);
open my $L, '<', $Lfile or die $!;
open my $R, '<', $Rfile or die $!;
while ( <$L> ) {
my ($comp) = /([^,]*,[^,]*,[^,]*)/;
$Llist{$comp} = $_;
}
while ( <$R> ) {
my ($comp) = /([^,]*,[^,]*,[^,]*)/;
if ( $Llist{$comp} ) {
push @common, delete $Llist{$comp};
} else {
push @Rlist, $_;
}
}
print "Llist only:\n", values %Llist, "\n";
print "Rlist only:\n", @Rlist, "\n";
print "In common:\n", @common;
This is a simplified example, though. Consider, for instance, the
possibility that there is a company named "Smith, Jones & Co". To deal
with that, you'd better use a CSV module for parsing the records.
--
Gunnar Hjalmarsson
Email: http://www.gunnar.cc/cgi-bin/contact.pl
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