Filter

Returns the option if it IsSome and the predicate function returns true when applied it. Otherwise, returns an Option<T>.None().

Parameter	Returns
Func<T, bool> predicate Option<T> option	Option<T>

Usage

When the option value IsNone or when the option value IsSome and the predicate function returns true, this function will returns the option parameter as a result.

Otherwise, returns an Option<T>.None().

When the option value IsSome and predicate returns true

Option<int> optionValue = 4;
Option<int> result = optionValue.Filter(value => value % 2 == 0);

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

When the option value IsSome and predicate returns false

Option<int> optionValue = 3;
Option<int> result = optionValue.Filter(value => value % 2 == 0);

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

When the option value IsNone

Option<int> optionValue = Option<int>.None();
Option<int> result = optionValue.Filter(value => value % 2 == 0);

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