(a -> Bool) -> [a] -> Maybe a

The find function takes a predicate and a list and returns the first element in the list matching the predicate, or Nothing if there is no such element. For the result to be Nothing, the list must be finite.

>>> find (> 4) [1..]
Just 5

>>> find (< 0) [1..10]
Nothing

lookupBy :: (a -> Bool) -> [a] -> Maybe a

HaXml Text.XML.HaXml.Schema.Parse

An auxiliary you might expect to find in Data.List

find :: (a -> Bool) -> [a] -> Maybe a

prelude-compat Data.List2010

match' :: () => (a -> Bool) -> [a] -> Maybe a

ENIG Data.Text.ENIG

findSucc :: (a -> Bool) -> [a] -> Maybe a

zenacy-html Zenacy.HTML.Internal.Core

Finds the element in a list that is the succeessor of the element matching a predicate.

find :: Foldable t => (a -> Bool) -> t a -> Maybe a

The find function takes a predicate and a structure and returns the leftmost element of the structure matching the predicate, or Nothing if there is no such element.

Examples

Basic usage:

>>> find (> 42) [0, 5..]
Just 45

>>> find (> 12) [1..7]
Nothing

find :: Foldable t => (a -> Bool) -> t a -> Maybe a

rio RIO.List, base-prelude BasePrelude, LambdaHack Game.LambdaHack.Core.Prelude

The find function takes a predicate and a structure and returns the leftmost element of the structure matching the predicate, or Nothing if there is no such element.

find :: Vector v a => (a -> Bool) -> v a -> Maybe a

vector Data.Vector.Generic, rio RIO.Vector

O(n) Yield Just the first element matching the predicate or Nothing if no such element exists.

find :: Vector v a => (a -> Bool) -> v a -> Maybe a

fixed-vector Data.Vector.Fixed

The find function takes a predicate and a vector and returns the leftmost element of the vector matching the predicate, or Nothing if there is no such element.

gfind :: GFoldable t => (a -> Bool) -> t a -> Maybe a

generic-deriving Generics.Deriving.Foldable

findIndex :: C n => (a -> Bool) -> [a] -> Maybe n

numeric-prelude NumericPrelude.List.Generic