programming-examples/perl/Hash/To tell if a given key name exists in a hash, you can use the exists operator.pl

#if ( exists($hash{$key} ) ) {
#  # ..
#}


$hash{"Name"} = "A";
$hash{"Address"} = "B";
$hash{"City"} = "C";

if ( exists($hash{"City"} ) ) {
  print 'exists';
}