tryGetValue.md

Option.tryGetValue

Namespace: FsToolkit.ErrorHandling

tryGetValue tries to get the value associated with a key from a dictionary. Returns Some value if the key exists, or None if it does not.

Note: This function is not available when using Fable (JavaScript/Python compilation).

Function Signature

'key -> ^Dictionary -> ^value option

where ^Dictionary has a member TryGetValue: 'key * byref<^value> -> bool.

Examples

Example 1 — Key exists

open System.Collections.Generic

let dict = Dictionary<string, int>()
dict["apples"] <- 5
dict["bananas"] <- 3

let result : int option =
    dict
    |> Option.tryGetValue "apples"

// Some 5

Example 2 — Key does not exist

open System.Collections.Generic

let dict = Dictionary<string, int>()
dict["apples"] <- 5

let result : int option =
    dict
    |> Option.tryGetValue "bananas"

// None