Map

Creates a new Option<T> whose value is the result of applying the given mapping function to Option<T>.Some value.

Otherwise returns an Option<T>.None.

Usage

This function is usually used to modify an optional value by applying a given regular function. For instance, With this method is possible to apply an function that receive an int to an Option<int>.

This function uses the Match method to get the encapsulated value by Option<T>, applies the mapping function and encapsulate the result.

When the option value IsSome

Option<int> optionValue = 4;
Option<int> result = optionValue.Map(value => value * 2);

//result.IsSome = true
//result.Some = 8

When the option value IsSome and the Map function modifies its type

Option<int> optionValue = 4;
Option<string> result = optionValue.Map(value => value.ToString());

//result.IsSome = true
//result.Some = "4"

When the option value IsSome (with named function)

int SquareAndDouble(int value)
{
    return value * value * 2;
}

Option<int> optionValue = 4;
Option<int> result = optionValue.Map(SquareAndDouble);

//result.IsSome = true
//result.Some = 32

When the option value IsNone

Option<int> optionValue = Option<int>.None();
Option<int> result = optionValue.Map(value => value * 2);

//result.IsSome = false
//result.IsNone = true