Map

Properties

• Map.len: the number of key-value pairs in the map.
• Map.keys: the keys in the map as a list.
• Map.items: the items in the map as a list.

Example

var m = { a = 1, b = 2, c = 3 }
print(m.len)   // 3
print(m.keys)   // ["a", "b", "c"]
print(m.items)   // [1, 2, 3]

Map.clear

The Map.clear method removes all key-value pairs from the map.

Syntax

Map.clear()

Parameters

None.

Return Value

None.

Example

var m = {a = 1, b = 2, c = 3}
m.clear()
print(m)  // {}

Map.contains

The Map.contains method checks wether the map contains a certain key.

Syntax

Map.contains(key)

Parameters

• key: The key to check for in the map.

Return Value

true if the map contains the specified key, and false otherwise.

Example

var m = {a = 1, b = 2, c = 3}
print(m.contains("a"))  // true
print(m.contains("d"))  // false

Map.delete

The Map.delete method removes the key-value pair with the specified key from the map.

Syntax

Map.delete(key)

Parameters

• key: The key of the key-value pair to delete from the map.

Return Value

None.

Example

var m = {a = 1, b = 2, c = 3}
m.delete("b")
print(m)  // {a = 1, c = 3}
print(m.contains("b"))  // false

Map.copy

The Map.copy method returns a new map that is a shallow copy of the original map.

Syntax

Map.copy()

Parameters

None.

Return Value

A new map that is a shallow copy of the original map.

Example

var m = {a = 1, b = 2, c = 3}
var n = m.copy()
print(m == n)  // true
print(m is n)  // false