Hashes

Hashes map keys to values. They are written as a list of key-value pairs, separated by colons (:). The keys may only contain letters, numbers, and underscores.

key1: value1
key2: value2

The values can be any yaml value, even other hashes.

key1: value1
level1: # the value of this key is a hash
  key2: value2
  level2: # the value of this key is a hash
    key3: value3

The order of the keys in a hash has no meaning. The following two hashes are identical.

some_key: value1
another_key: value2

another_key: value2
some_key: value1

An empty hash can be written as {}.

empty_subhash: {}