Builds a map that contains the bindings of the given IEnumerable.

elements : seq<'Key * 'Value>

The input sequence of key/value pairs.

Returns: Map<'Key, 'Value>

The resulting map.

Example

 Map [ (1, "a"); (2, "b") ] // evaluates to map [(1, "a"); (2, "b")]

Returns a new map with the binding added to the given map. If a binding with the given key already exists in the input map, the existing binding is replaced by the new binding in the result map.

key : 'Key

The key to add.

value : 'Value

The value to add.

Returns: Map<'Key, 'Value>

The resulting map.

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 sample.Add (3, "c") // evaluates to map [(1, "a"); (2, "b"); (3, "c")]
 sample.Add (2, "aa") // evaluates to map [(1, "a"); (2, "aa")]

Returns a new map with the value stored under key changed according to f.

key : 'Key

The input key.

f : 'Value option -> 'Value option

The change function.

Returns: Map<'Key, 'Value>

The resulting map.

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 let f x =
     match x with
     | Some s -> Some (s + "z")
     | None -> None

 sample.Change (1, f) // evaluates to map [(1, "az"); (2, "b")]

Tests if an element is in the domain of the map.

key : 'Key

The input key.

Returns: bool

True if the map contains the given key.

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 sample.ContainsKey 1 // evaluates to true
 sample.ContainsKey 3 // evaluates to false

The number of bindings in the map.

Returns: int

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 sample.Count // evaluates to 2

Returns true if there are no bindings in the map.

Returns: bool

Example

 let emptyMap: Map<int, string> = Map.empty
 emptyMap.IsEmpty // evaluates to true

 let notEmptyMap = Map [ (1, "a"); (2, "b") ]
 notEmptyMap.IsEmpty // evaluates to false

Lookup an element in the map. Raise KeyNotFoundException if no binding exists in the map.

key : 'Key

The input key.

Returns: 'Value

The value mapped to the key.

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 sample.[1] // evaluates to "a"
 sample.[3] // throws KeyNotFoundException

The keys in the map. The sequence will be ordered by the keys of the map.

Returns: ICollection<'Key>

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 sample.Keys // evaluates to seq [1; 2]

Removes an element from the domain of the map. No exception is raised if the element is not present.

key : 'Key

The input key.

Returns: Map<'Key, 'Value>

The resulting map.

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 sample.Remove 1 // evaluates to map [(2, "b")]
 sample.Remove 3 // equal to sample

Lookup an element in the map, returning a Some value if the element is in the domain of the map and None if not.

key : 'Key

The input key.

Returns: 'Value option

The mapped value, or None if the key is not in the map.

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 sample.TryFind 1 // evaluates to Some "a"
 sample.TryFind 3 // evaluates to None

Lookup an element in the map, assigning to value if the element is in the domain of the map and returning false if not.

key : 'Key

The input key.

value : byref<'Value>

A reference to the output value.

Returns: bool

true if the value is present, false if not.

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 sample.TryGetValue 1 // evaluates to (true, "a")
 sample.TryGetValue 3 // evaluates to (false, null)

 let mutable x = ""
 sample.TryGetValue (1, &x) // evaluates to true, x set to "a"

 let mutable y = ""
 sample.TryGetValue (3, &y) // evaluates to false, y unchanged

All the values in the map, including the duplicates. The sequence will be ordered by the keys of the map.

Returns: ICollection<'Value>

Example

 let sample = Map [ (1, "a"); (2, "b") ]

 sample.Values // evaluates to seq ["a"; "b"]