I forgot to cc: the list...
2009/12/10 Noah <noah-l...@enabled.com>:
> I am hoping to figure out the best Way to write something. I have two
> arrays @previous_hostnames and @hostnames.
>
> I want to figure out if there is at least one matching element in
> @previous_hostnames that is found in @hostnames.
You can use a lookup table to eliminate one loop:
my %previous_hostnames = map { $_ => 1 } @previous_hostnames;
for my $hostname (@hostnames) {
if ($previous_hostname{$hostname}) {
$found = 1;
last;
}
}
The first line builds a hash with keys being previous hostnames with
values 1 for every one of them. Now you only have to check if
$previous_hostname{$hostname} is true. Usually when you are comparing
a string to a list of strings you should use a lookup table for best
performance.
Or you can use Quantum::Superpositions:
use Quantum::Superpositions;
my $found = 1 if any(@hostnames) eq any(@previous_hostnames);
By the way, you have to use eq instead of == if you want to compare
strings or otherwise you are comparing your hostnames as numbers which
is probably not what you want. For example:
"a" == "b" is true because both are 0 when converted to numbers
"a" eq "b" is false because eq compares strings
See: http://perldoc.perl.org/perlop.html#Equality-Operators
Rafał Pocztarski
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