Map0.28.0

Overview
Properties
Methods

external class Map<out Key, out Value> extends Any

A mapping from keys to values.

Known subtypes:
Known usages:
All versions:

Maps retain the order of entries when constructed, which affects the how they are iterated over. However, ordering of entries does not affect equality between two maps.

The following operators are supported for maps:

map[key]     // subscript; similar to `getOrNull` but throws if key not found
map1 + map2  // merge; if both maps have an entry with the same key, the entry in map2 wins

Properties

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length: Int

The number of entries in this map.
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isEmpty: Boolean

Tells whether this map is empty.
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keys: Set<Key>

The keys contained in this map.
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values: List<Value>

The values contained in this map.
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entries: List<Pair<Key, Value>>

The entries contained in this map.

Methods(show inherited)

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function

Any.getClass(): Class (pkl.base)

Returns the class of this.
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function

Any.toString(): String (pkl.base)

Returns a string representation of this.

This method is used to convert the values of string interpolation expressions to strings.
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Any.ifNonNull<Result>(transform: (NonNull) -> Result): Result? (pkl.base)

Returns this |> transform if this is non-null, and null otherwise.

This method is the complement of the ?? operator and the equivalent of an Option type's map and flatMap methods.
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function

getOrNull(key: Any): Value?

Returns the value for key.

Returns null if this map does not contain key.
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function

containsKey(key: Any): Boolean

Tells if this map contains an entry with the given key.
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function

containsValue(value: Any): Boolean

Tells if this map contains an entry with the given value.
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function

put<NewKey, NewValue>(key: NewKey, value: NewValue): Map<(NewKey|Key), (NewValue|Value)>

Adds or updates key to value.
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function

remove(key: Any): Map<Key, Value>

Removes the map entry with the given key.

Returns this map unchanged if it does not contain an entry with the given key.
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filter(predicate: (Key, Value) -> Boolean): Map<Key, Value>

Removes all entries for which predicate does not hold.
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fold<Result>(initial: Result, operator: (Result, Key, Value) -> Result): Result

Folds the entries of this map in iteration order using operator, starting with initial.
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map<NewKey, NewValue>(transform: (Key, Value) -> Pair<NewKey, NewValue>): Map<NewKey, NewValue>

Transforms the entries of this map using transform.
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mapKeys<NewKey>(transform: (Key, Value) -> NewKey): Map<NewKey, Value>

Transforms the keys of this map using transform.
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mapValues<NewValue>(transform: (Key, Value) -> NewValue): Map<Key, NewValue>

Transforms the values of this map using transform.
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flatMap<NewKey, NewValue>(transform: (Key, Value) -> Map<NewKey, NewValue>): Map<NewKey, NewValue>

Applies a map-generating transform to each map entry and concatenates the resulting maps.
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every(predicate: (Key, Value) -> Boolean): Boolean

Tells if predicate holds for every entry of this map.

Returns true for an empty map.
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any(predicate: (Key, Value) -> Boolean): Boolean

Tells if predicate holds for at least one entry of this map.

Returns false for an empty map.
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toMap(): Map

Returns this map.
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toDynamic(): Dynamic

Converts this map to a Dynamic object.
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toTyped<Type>(clazz: Class): Type(this is Typed)

Converts this map to a typed object of class clazz.
Conforms to the semantics of the following manual conversion:
```
class Person { name: String; age: Int }
map = Map(name, "Pigeon", age, 42)
function toTyped(map: Map): Person = new {
  name = map.getOrNull("name") ?? super.name
  age = map.getOrNull("age") ?? super.age
}
```
Notable behavior:
- Entries of this that have no corresponding property in clazz are ignored.
- clazz properties that have no corresponding entry in this have their defaults preserved.
- clazz properties that have neither a default nor a corresponding entry in this throw an "undefined property" error (only) when accessed.
Throws if clazz is abstract or not a subclass of Typed.
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toMapping(): Mapping<Key, Value>

Converts this map to a Mapping.