Check if element in One Array Exist in Other Array

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

Guys,
I want to check two array refs. Let's call it $test1 and $test2 with another fixed source array called: $source. Now what I intend to get is, whenever an element in $test1 or $test2 doesn't exist in $source. It should return false. Is there a quick way to do this?
I'm kinda stuck with my code below.

$test1 = ['A','D','B'];
$test2 = ['A','C','B'];
$source = ['A','B','C','A','B'];

check_array($test1,$source); # Should return False
                             # since "D" doesn't exist in 
                             # $source


check_array($test2,$source); # Should return True
                             # since all element exist in 
                             # $source

check_array($test1,$source);

sub check_array
{
    my  ($test,$source) = @_;

    OUT:
    foreach  my $ts ( @{$test}  )
    {
        foreach  my $sc (@{$source}  )
        {
            if ( $ts ne $sc )
            {
                print "FALSE\n";
                last OUT;
            }
            else
            {
              print "TRUE\n";
            }
        }
    }

    return ;
}

Thanks beforehand.
[download]

Comment on Check if element in One Array Exist in Other Array Select or Download Code

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Re: Check if element in One Array Exist in Other Array by gopalr (Priest) on Oct 13, 2005 at 06:18 UTC
Take a look at List::Compare::Functional Module. Update `use List::Compare::Functional qw(is_LsubsetR); $test1 = ['A','D','B']; $test2 = ['A','C','B']; $source = ['A','B','C','A','B']; $result = is_LsubsetR( [ $test1, $source ] ); $result == 1 ? print "\n\$test1 is True" : print "\n\$test1 is False"; $result = is_LsubsetR( [ $test2, $source ] ); $result == 1 ? print "\n\$test2 is True" : print "\n\$test2 is False";` [download] OUTPUT `$test1 is False $test2 is True` [download]	[reply] [d/l] [select]
Re: Check if element in One Array Exist in Other Array by Ovid (Cardinal) on Oct 13, 2005 at 06:20 UTC
Unless I have seriously misunderstood you, the following should suffice. #!/usr/bin/perl -l use strict; use warnings; my $test1 = [ 'A', 'D', 'B' ]; my $test2 = [ 'A', 'C', 'B' ]; my $source = [ 'A', 'B', 'C', 'A', 'B' ]; print "yes 1" if check_array( $test1, $source ); # Should return Fa +lse # since "D" doesn' +t exist in # $source print "yes 2" if check_array( $test2, $source ); # Should return Tr +ue # since all elemen +t exist in # $source sub check_array { my ( $test, $source ) = @_; my %exists = map { $_ => 1 } @$source; foreach my $ts ( @{$test} ) { return if ! $exists{$ts}; } return 1; } [download] Cheers, Ovid New address of my CGI Course.	[reply] [d/l]
Re: Check if element in One Array Exist in Other Array by graff (Chancellor) on Oct 13, 2005 at 06:44 UTC
If you really are always comparing things to a single "source" array that doesn't change, you should just make it a hash instead of an array. That's basically what Ovid does in his subroutine, but doing it in the sub means you re-build the hash every time you call it. So, wherever you actually put values into your source array, instead of doing it this way: `@source = ( ... );` [download] just do it this way: `%source = map { $_ => undef } ( ... );` [download] Then your check_array sub is just the for loop: `sub check_array { my ( $array, $source ) = @_; for ( @$array ) { return if ( ! exists( $$source{$_} )); } return 1; }` [download]	[reply] [d/l] [select]
Re: Check if element in One Array Exist in Other Array by Rajeshk (Scribe) on Oct 13, 2005 at 07:41 UTC
$a = ['A','B','D']; $b = ['B','E','F']; $source = ['A','B','C','E','F']; $x = &check_array($a, $source); print "First Comparison = $x\n"; $x = &check_array($b, $source); print "Second Comparison = $x\n"; sub check_array{ my ($a, $source) = @_; foreach my $elt (@$a){ return 1 unless(grep /$elt/, @$source); } return 0; }	[reply]
Re: Check if element in One Array Exist in Other Array by Skeeve (Parson) on Oct 13, 2005 at 06:10 UTC
You bail out as soon asthe first element of @$test doesn't equal all elements of @$source. `foreach my $ts ( @{$test} ) { foreach my $sc (@{$source} ) { if ( $ts ne $sc ) # <- You will fail here { print "FALSE\n";` [download] See what's compared in the line marked above: `1. loop: 'A' ne 'A' -> okay. They are equal 2. loop: 'A' ne 'B' -> TRUE So fail...` [download] `s$$([},&%#}/&/]+}%&{});#$&&s&&$^X.($'^"%]=\&(\|?{%` `+`.+=%;.#_}\&"^"-+%*).}%:##%}={~=~:.")&e&&s""`$''`"e	[reply] [d/l] [select]