Using merlyn's example with regular expressions, so you don't need to know the exact value of the element you are matching;

my @array = ( 'Name: Mr. Jones', 
              'Phone: 555-555', 
              'Email: jones@example.com' 
);
my ( $index )= grep { $array[$_] =~ /Phone/ } 0..$#array;
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Replace ( $index ) with an array to match multiple instances.