Loyc.Collections.SelectDictionaryFromKeys< K, V > Class Template Reference

An adapter that converts a collection of keys to an IReadOnlyDictionary. Used by EnumerableExt.AsReadOnlyDictionarybased on a function that can obtain a value for a given key. More...

---

Source file:

• /Core/Loyc.Essentials/Collections/Adapters/SelectDictionaryFromKeys.cs

Inheritance diagram for Loyc.Collections.SelectDictionaryFromKeys< K, V >:

Remarks

An adapter that converts a collection of keys to an IReadOnlyDictionary. Used by EnumerableExt.AsReadOnlyDictionarybased on a function that can obtain a value for a given key.

Template Parameters

K	Key type
V	Value type

Public fields
IEnumerable< K >	Keys => _keys
IEnumerable< V >	Values
int	Count => _keys.Count

Properties
V	this[K key] [get]

Public Member Functions
	SelectDictionaryFromKeys (IReadOnlyCollection< K > keys, Func< K, Maybe< V >> tryGetValue, Func< K, V > getValue=null)
	Initializes the adapter. More...
bool	ContainsKey (K key)
IEnumerator< KeyValuePair< K, V > >	GetEnumerator ()
bool	TryGetValue (K key, out V value)

Constructor & Destructor Documentation

SelectDictionaryFromKeys()

Loyc.Collections.SelectDictionaryFromKeys< K, V >.SelectDictionaryFromKeys ( IReadOnlyCollection< K >  keys, Func< K, Maybe< V >>  tryGetValue, Func< K, V >  getValue = null  )

inline

Initializes the adapter.

Parameters

keys	A collection of dictionary keys.
tryGetValue	This function is used both to test membership and to get values.
getValue	This function is optional. It is used to get values when it is known in advance that the key exists (in GetEnumerator() and in the Values property). If this is null, tryGetValue is used instead. Providing this function can increase performance.

Member Data Documentation

Values

IEnumerable<V> Loyc.Collections.SelectDictionaryFromKeys< K, V >.Values

Initial value:

=> _getValue != null 
            ? _keys.Select(k => _getValue(k))
            : _keys.Select(k => _tryGetValue(k).Or(default(V)))