Map functions and operators

Map functions

map_access

Returns the value of the map for the given key. Returns null if the key is not found.

map_access ( map, key ) → value

map_access(MAP{1:100,2:200}, 1) -> 100
map_access(MAP{1:100,2:200}, 3) -> null

map_cat

Concatenates two maps. If the same key is present in both maps, the value from the second map is used.

map_cat ( map, map ) → map

map_cat (MAP{1:100,2:200}, MAP{2:201,3:300}) -> {1:100,2:201,3:300}

map_contains

Returns true if the map contains the given key, false otherwise.

map_contains ( map, key ) → boolean

map_contains(MAP{1:100,2:200}, 1) -> true
map_contains(MAP{1:100,2:200}, 3) -> false

map_delete

Deletes a key-value pair from the map. No-op if the key is not found.

map_delete ( map, key ) → map

map_delete(MAP{1:100,2:200}, 1) -> {2:200}
map_delete(MAP{1:100,2:200}, 3) -> {1:100,2:200}

map_entries / map_keys / map_values

Returns an array of key-value pairs, keys, or values of the map.

map_entries ( map ) → array
map_keys ( map ) → array
map_values ( map ) → array

map_entries(MAP{1:100,2:200}) -> array[row(1,100),row(2,200)]
map_keys(MAP{1:100,2:200}) -> array[1,2]
map_values(MAP{1:100,2:200}) -> array[100,200]

map_filter

Added in v2.5.0. It is currently in technical preview stage.

Filters a map using a lambda function and returns key-value pairs that satisfy the condition.

map_filter ( map, function ) → map

map_filter(MAP{'a':1, 'b':2, 'c':3}, |k, v| v > 1) -> {b:2,c:3}

map_from_entries

Constructs a map from an array of key-value pairs.

map_from_entries ( array ) → map

map_from_entries(array[row('key1',1), row('key2',2), row('key3',3)]) -> {key1:1,key2:2,key3:3}

map_from_key_values

Constructs a map from an array of keys and an array of values.

map_from_key_values ( array, array ) → map

map_from_key_values(array['key1','key2','key3'], array[1,2,3]) -> {key1:1,key2:2,key3:3}

map_length

Returns the number of key-value pairs in the map.

map_length ( map ) → int

map_length(MAP{1:100,2:200}) -> 2

map_insert

Inserts a key-value pair into the map. If the key is already present, the value is updated.

map_insert ( map, key, value ) → map

map_insert(MAP{1:100,2:200}, 3, 300) -> {1:100,2:200,3:300}
map_insert(MAP{1:100,2:200}, 1, 101) -> {2:200,1:101}

Map operators

map [key] -> value

Alias of map_access.

MAP{1:100,2:200}[1] → 100
MAP{1:100,2:200}[3] → null