perl hash
# Basic syntax: my %your_hash = ( key_1 => "value_1", key_2 => "value_2", key_3 => "value_3", ); # Where: # - The % is used to denote a hash # - key:value pairs are denoted with key => "value" syntax Add a key:value pair to a hash: $your_hash{new_key} = "new_value" # Remove a key:value pair from a hash: delete $your_hash{key_1} # Access a specific value from a hash: my %fruit_color = ( apple => "red", banana => "yellow", ); print "$fruit_color{'apple'}\n"; --> Red # All of the keys or values that exist in a hash can be accessed using # the "keys" and "values" functions. Here we assign the results to arrays: my @fruits = keys %fruit_color; my @colors = values %fruit_color; # It's possible to iterate through keys (or values) with a foreach loop: foreach my $fruit (keys %fruit_color) { print "$fruit\n"; } --> apple --> banana # Check if hash contains a particular key: if (exists $fruit_color{orange}) {print "The hash contains orange\n"}
Source: korflab.ucdavis.edu