Map.containsKey<'Key,'T> Function (F#)
Tests if an element is in the domain of the map.
Namespace/Module Path: Microsoft.FSharp.Collections.Map
Assembly: FSharp.Core (in FSharp.Core.dll)
// Signature:
Map.containsKey : 'Key -> Map<'Key,'T> -> bool (requires comparison)
// Usage:
Map.containsKey key table
Parameters
key
Type: 'KeyThe input key.
table
Type: Map<'Key,'T>The input map.
Return Value
true if the map contains the key.
Remarks
This function is named ContainsKey in compiled assemblies. If you are accessing the function from a language other than F#, or through reflection, use this name.
Example
The following code shows how to use Map.containsKey.
let map1 = Map.ofList [ (1, "one"); (2, "two"); (3, "three") ]
let findKeyAndPrint key map =
if (Map.containsKey key map) then
printfn "The specified map contains the key %d." key
else
printfn "The specified map does not contain the key %d." key
findKeyAndPrint 1 map1
findKeyAndPrint 0 map1
Output
The specified map contains the key 1. The specified map does not contain the key 0.
Platforms
Windows 7, Windows Vista SP2, Windows XP SP3, Windows XP x64 SP2, Windows Server 2008 R2, Windows Server 2008 SP2, Windows Server 2003 SP2
Version Information
F# Runtime
Supported in: 2.0, 4.0
Silverlight
Supported in: 3