searching a list, i always like binary search.
of course, the list has to be sorted tough.
here is a little script
use strict;
use warnings;
my @s = ( 'abc', 'dog', 'cat', 'rabbit', 'attic' );
my @sorted_copy = sort { $a cmp $b } @s;
print ' at:' . contains_string( 'at', \@sorted_copy ) . "\n";
print 'cat:' . contains_string( 'cat', \@sorted_copy ) . "\n";
sub contains_string {
my ( $var, $array ) = @_;
return binary_string_search( $var, $array ) > -1;
}
sub binary_string_search {
my ( $var, $array, $lo, $hi ) = @_;
$lo = 0 unless defined $lo;
$hi = $#{ @{$array} } unless defined $hi;
while ( $lo <= $hi ) {
# determine new division point
my $mid = $lo + int( ( $hi - $lo ) / 2 );
if ( $array->[$mid] eq $var ) {
return $mid;
}
elsif ( $var le $array->[$mid] ) {
$hi = $mid - 1;
}
else {
$lo = $mid + 1;
}
}
# nothing found
return -1;
}
i think you can achieve a speedy solution when searching a big list for more than one item.
UPDATE: minor code changes.
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