Map module

The Map module contains functions to manipulate maps (dicts). The keys and values can be of any type.

new/0

Map.new() # empty map

Returns an empty map. There is no shorthand notation.

size/1

Map.size(key1: "value", key2: "value2") # 2

Parameters:

• map the map

Returns the number of keys in map.

get/2

Map.get([key1: "value", key2: "value2"], "key1") # "value"
Map.get([key1: "value", key2: "value2"], "key3") # nil

Parameters:

• map the map
• key the key

Returns the value at key in map or nil if key is not in the map.

tip

There is a shorthand notation map.key when key is not a variable.

get/3

Map.get([key1: "value", key2: "value2"], "key1", "not in map") # "value"
Map.get([key1: "value", key2: "value2"], "key3", "not in map") # "not in map"

Parameters:

• map the map
• key the key
• default the default value

Returns the value at key in map or default if key is not in the map.

set/3

Map.set([key1: "value", key2: "value2"], "key1", "valueX") # [key1: "valueX", key2: "value2"]
Map.get([key1: "value", key2: "value2"], "key3", "value3") # [key1: "value", key2: "value2, key3: "value3"]

Parameters:

• map the map
• key the key
• value the value to set

Returns a copy of map where the value at key is value.

keys/1

Map.keys(key1: "value", key2: "value2") # ["key1", "key2"]

Parameters:

• map the map

Returns the list of keys in map.

tip

Use it with a for loop to iterate on a map!

for key in Map.keys(map) do
    ...
    value = map[key]
    ...
end

values/1

Map.values(key1: "value", key2: "value2") # ["value", "value2"]

Parameters:

• map the map

Returns the list of values in map.

delete/2

Map.delete([key1: "value", key2: "value2"], "key2") # [key1: "value"]

Parameters:

• map the map
• key the key to remove

Returns a copy of the map without the value at given key.