In simple terms, use map for transformation and grep for filtering.

See the following code snippet

my @ints = qw(1 2 3 4 5);

my @doubleints = map { $_ * 2 } @ints;

my @odds = grep { $_ % 2 } @ints;

print "INTS = " . join(",", @ints) . "\n";

print "DOUBLE = " . join(",", @doubleints) . "\n";

print "ODDS = " . join(",", @odds) . "\n";


----------- OUTPUT ------
INTS = 1,2,3,4,5
DOUBLE = 2,4,6,8,10
ODDS = 1,3,5
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Update: Thanks to bart for pointing out that I had not closed the italics - used <i> instead of </i> for closing tag.

Mahesh