Problems with Comparing Arrays

dru145 has asked for the wisdom of the Perl Monks concerning the following question:

Folks,

I have an array @emails with the following elements

mgr@acme.net
ipadm@acme.net
abuse@acme.net
mgr@acme.net
ipadm@acme.net
abuse@acme.net
[download]

I want to remove the duplicates, so I'm using this little piece of code:

my @saw; 
@emails = grep(!$saw[$_]++, @emails);
[download]

When I print out @emails running -w and strict, I get the following output:

Argument "mgr@acme.net" isn't numeric in array element at ./whois.pl l
+ine 64.
Argument "ipadm@acme.net" isn't numeric in array element at ./whois.pl
+ line 64.
Argument "abuse@acme.net" isn't numeric in array element at ./whois.pl
+ line 64.
Argument "mgr@acme.net" isn't numeric in array element at ./whois.pl l
+ine 64.
Argument "ipadm@acme.net" isn't numeric in array element at ./whois.pl
+ line 64.
Argument "abuse@acme.net" isn't numeric in array element at ./whois.pl
+ line 64.
mgr@acme.net
[download]

What should I do to supress these warnings?

Thanks,
Dru
Another satisfied monk.

Comment on Problems with Comparing Arrays Select or Download Code

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Re: Problems with Comparing Arrays by danboo (Beadle) on Dec 28, 2001 at 02:48 UTC
change it to: `my %saw; # note the hash @emails = grep(!$saw{$_}++, @emails); # note the curlies` [download]	[reply] [d/l]
Re: Problems with Comparing Arrays by grep (Monsignor) on Dec 28, 2001 at 02:48 UTC
You want a hash not an array for @saw. `#!/usr/bin/perl -w use strict; my @emails = qw/mgr@acme.net ipadm@acme.net abuse@acme.net mgr@acme.net ipadm@acme.net abuse@acme.net /; my %saw; @emails = grep(!$saw{$_}++, @emails); foreach (keys %saw) { print "$_\n"; }` [download] grep grep> cd pub grep> more beer	[reply] [d/l]
Re: Problems with Comparing Arrays by dmmiller2k (Chaplain) on Dec 28, 2001 at 03:38 UTC
Whoops! You're using an array as if it were a hash. Are you fluent in AWK, by chance? Associative arrays in AWK are analagous to hashes in Perl, but their usage looks no different than that of regular arrays. You need to explicitly declare array `@saw` as a hash, e.g., `%saw`, and change the square brackets you are using to curly braces, as mentioned elsewhere in this thread. dmm You can give a man a fish and feed him for a day ... Or, you can teach him to fish and feed him for a lifetime	[reply] [d/l] [select]