Glossary

• Hash - A collection of key-value pairs with unique keys.
• Hash Rocket - An operator for mapping keys to values in a hash: =>.

Hash Methods

• has_key?(key) - Returns a boolean indicating whether its argument is a key in the hash.
• has_value?(val) - Returns a boolean indicating whether its argument is a value in the hash.
• include?(key) - Returns a boolean indicating whether its argument is a key in the hash.
• keys - Returns an array of all the keys in its receiver.
• key?(key) - Returns a boolean indicating whether its argument is a key in the hash.
• length - Returns the number of key-value pairs in its receiver.
• to_a - Type converts its receiver hash into a nested array of [key, value] arrays.
• to_h - Type converts a nested array of two-element arrays to a hash.
• values - Returns an array of all the values in its receiver.
• value?(val) - Returns a boolean indicating whether its argument is a value in the hash.