A YCP-map is an associative array. It is a list of key-value-pairs with the keys being non-ambiguous, i.e. there are no two keys being exactly equal. While you can use values of any type for keys and values, you should restrict the keys to be of type string because from experience other types tend to complicate the code. Values of arbitrary type on the other hand make the map a very flexible data container. Maps are denoted with $[ key_0:value_0, key_1:value_1, ...]. The empty map is denoted by $[].

Note: A map does not reserve order of its elements when iterating over them.

$[ ]
$[ "/usr": 560, "/home" : 3200 ]
$[ "first": true, "2": [ true, false ], "number" : 8+9 ]

Accessing the map elements is done by means of the index operator as in my_map["os_type"]:"linux". This returns the value associated with the key "os_type". As with lists, a default value must be appended (after a colon) that is returned if the given key does not exist. Again it should have the type that is expected for the current access, in this case the string “linux”.

You may have noticed that the syntax for accessing maps kind of resembles that of accessing lists. This is due to the fact that lists are realized as maps internally with constant keys 0, 1, 2, and so on.

Note: There is also another method for accessing maps, originating from the early days of YaST. The command lookup(my_map, "os_type", "linux") also returns the value associated with the given key. While this still works, it is deprecated by now and may be dropped in the future.