Tango
  • Introduction
  • Getting Started
    • Summary
    • From me, the Developer
    • What is Tango?
    • Where to start?
  • Installation
    • Based on NuGet
    • Manually
  • Fundamentals
    • Introduction
    • Using Pattern Matching
    • Option values
    • Either values
    • From void to Unit
    • Func and Action
    • Chainable operations in a Continuation flow
    • Currying and Partial Application
  • Functional
    • Introduction
    • Currying
    • Partial Application
    • Functional Extensions
    • QuickCast to Delegates
  • Operations
    • Introduction
    • Operations with Booleans
    • Operations with Integers
    • Operations with Decimals
    • Operations with Doubles
    • Operations with Strings
  • Types
    • Introduction
    • Unit
    • Option<T>
    • Either<TLeft, TRight>
    • Continuation<TFail, TSuccess>
  • Modules
    • Introduction
    • Option
      • Apply
      • AsEnumerable
      • Bind
      • Count
      • Exists
      • Filter
      • Fold
      • FoldBack
      • Iterate
      • Map
      • OfNullable
      • ToArray
      • ToList
      • ToNullable
    • Either
      • Exists
      • Iterate
      • Fold
      • FoldBack
      • Map
      • Swap
      • ToTuple
    • Continuation
      • AsContinuation
      • Resolve
      • Reject
      • All
    • Collection
      • Append
      • Choose
      • ChunkBySize
      • Collect
      • CompareWith
      • CountBy
      • Concat
      • Distinct
      • Empty
      • Exists
      • Exists2
      • Filter
      • FindIndex
      • Fold
      • Fold2
      • FoldBack
      • FoldBack2
      • ForAll
      • ForAll2
      • ForAll3
      • Head
      • HeadAndTailEnd
      • Range
      • Generate
      • Initialize
      • Iterate
      • Iterate2
      • IterateIndexed
      • IterateIndexed2
      • Map
      • Map2
      • Map3
      • MapIndexed
      • MapIndexed2
      • MapIndexed3
      • Partition
      • Permute
      • Pick
      • Reduce
      • ReduceBack
      • Replicate
      • Scan
      • Scan2
      • ScanBack
      • ScanBack2
      • Tail
      • TryFind
      • TryPick
      • Unzip
      • Unzip3
      • Zip
      • Zip3
  • Extensions
    • Introduction
    • Enum Extensions
    • EqualityComparer Builder
    • Modules as Extensions
Powered by GitBook
On this page

Was this helpful?

  1. Modules
  2. Option

Exists

Returns true if the option IsSome and the predicate return true when applied it. Otherwise, returns false.

Parameters

Returns

Func<T, bool> predicate

Option<T> option

bool

Usage

When the Option<T> IsNone the results will be always false, Otherwise the predicate function will be applied to the Option and its returns will be the returned value.

When the option value IsSome and predicates returns true

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

//result = true

When the option value IsSome and predicates returns false

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

//result = false

When the option value IsNone

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

//result = false
PreviousCountNextFilter

Last updated 5 years ago

Was this helpful?