Map

Maps associate keys with values and provide fast lookups by key. Risor maps use underlying Go maps of type map[string]interface{}. This means Risor maps always operate with string keys, which provides equivalence with JSON.

>>> m := {one: 1, two: 2}
{"one": 1, "two": 2}
>>> m["three"] = 3
>>> m
{"one": 1, "three": 3, "two": 2}

Container Operations

>>> m := {"name": "sean", "age": 27}
{"age": 27, "name": "sean"}
>>> len(m)
2
>>> "age" in m
true
>>> m["age"]
27
>>> m["age"] = 28
>>> m
{"age": 28, "name": "sean"}
>>> m.keys()
["age", "name"]

Related Built-ins

delete(map, key)

Deletes the item with the specified key from the map. This operation has no effect if the key is not present in the map.

map(container)

Returns a new map with the contents of the given container. Generally, containers are transformed into the map by creating an iterator for the given container and the key and value for each iterator entry are added to the map. As a special case, if the container is a list then it is expected to be a nested list of key-value pairs, e.g. [["key1", "val1"]]. Any non-string keys that are encountered are automatically converted to their string representation.

>>> map({"a", "b", "c"})
{"a": true, "b": true, "c": true}
>>> map("abc")
{"0": "a", "1": "b", "2": "c"}
>>> map([["name", "joe"], ["age", 18]])
{"age": 18, "name": "joe"}

Methods

map.clear()

Removes all items from the map.

map.copy()

Returns a shallow copy of the map, containing the same keys and values.

map.get(key, default=nil)

Returns the value associated with the given key, if it exists in the map. If the key is not in the map, the given default value is returned.

map.items()

Returns a list of [key, value] pairs containing the items from the map.

map.keys()

Returns a sorted list of keys contained in the map.

map.pop(key, default=nil)

Returns the value associated with the given key and then removes it from the map. If the key is not in the map, the given default value is returned instead.

map.setdefault(key, default)

Sets the key to the given default value if the key is not already in the map. If the key already is in the map, do nothing. Returns the value associated with the key after the set action.

map.update(other)

Updates this map with the key-value pairs contained in the provided map, overwriting any items with matching keys already in this map.

map.values()

Returns a sorted list of values contained in the map.

List Bool