map

A map is an ordered key/value object.

Create a map with `map(…)`.

lookup = map();
lookup = map('x', 10, 'y', 20);

Keys are converted to strings.

Creates an empty map.

Example:

lookup = map();
lookup.empty();       // true

Creates a map initialized with key/value pairs.

Returns: map object.

The number of arguments must be even.

Example:

lookup = map('x', 10, 'y', 20);
lookup.get('x');      // 10

Map keys can be read as properties when the key is a valid property name.

lookup = map('x', 10);
lookup.x;             // 10

Property access is read-only. Use `set(key, value)` to change a map entry.

lookup.set('x', 20);

Returns a new map object with the same key/value pairs.

Example:

lookup = map('x', 10);
copy = lookup.clone();

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

Example:

map('x', 10, 'y', 20).size();  // 2

Alias for `size()`.

Example:

map('x', 10).count();          // 1

Returns true when the map has no entries.

Example:

lookup = map();
lookup.empty();                // true

Removes all entries from the map.

Example:

lookup = map('x', 10);
lookup.clear();
lookup.size();                 // 0

Checks whether a key exists.

Returns: boolean-style number.

Example:

lookup = map('x', 10);
lookup.has('x');               // true
lookup.has('z');               // false

Returns the value for a key.

Returns: stored value, or `none()` when the key does not exist.

Example:

lookup = map('x', 10);
lookup.get('x');               // 10
lookup.get('z').is_none();     // true

Stores a value for a key.

Returns: boolean-style number.

Example:

lookup = map();
lookup.set('x', 10);
lookup.get('x');               // 10

Removes a key/value pair.

Returns: true if a value was removed, false when the key did not exist.

Example:

lookup = map('x', 10);
lookup.remove('x');            // true
lookup.remove('x');            // false

Returns an array of keys in insertion order.

Example:

lookup = map('x', 10, 'y', 20);
lookup.keys().to_string();     // ["x", "y"]

Returns an array of values in insertion order.

Example:

lookup = map('x', 10, 'y', 20);
lookup.values().to_string();   // [10, 20]

Previous: array

Next: bytes