Hoogle Search
Within LTS Haskell 24.60 (ghc-9.10.3)
Note that Stackage only displays results for the latest LTS and Nightly snapshot. Learn more.
lookup :: Eq a => a -> [(a, b)] -> Maybe bcopilot-language Copilot.Language.Prelude lookup key assocs looks up a key in an association list. For the result to be Nothing, the list must be finite.
Examples
>>> lookup 2 [] Nothing
>>> lookup 2 [(1, "first")] Nothing
>>> lookup 2 [(1, "first"), (2, "second"), (3, "third")] Just "second"
lookup :: (OverloadedLookup t k v, Show k, Show t, MonadFail m, Applicative m) => k -> t -> m verror-or-utils Data.ErrorOr.Utils Overloaded lookup with good error messages.
lookup :: (AllocReaderM m, Key key, Value val) => key -> Tree key val -> m (Maybe val)haskey-btree Data.BTree.Impure Lookup a value in an impure B+-tree.
lookup :: (AllocReaderM m, Key key, Value val) => key -> Tree key val -> m (Maybe val)haskey-btree Data.BTree.Impure.Internal.Lookup Lookup a value in an impure B+-tree.
lookup :: Key k => k -> Tree k v -> Maybe vhaskey-btree Data.BTree.Pure Lookup a value in the tree.
lookup :: Eq a => a -> [(a, b)] -> Maybe blistsafe Data.List.Safe lookup key assocs looks up a key in an association list. For the result to be Nothing, the list must be finite.
Examples
>>> lookup 2 [] Nothing
>>> lookup 2 [(1, "first")] Nothing
>>> lookup 2 [(1, "first"), (2, "second"), (3, "third")] Just "second"
lookup :: Interface (m :: Type -> Type) -> Addr -> m (Maybe Addr)network-house Net.ARP_Protocol No documentation available.
-
pred-set Data.PredSet.Mutable No documentation available.
lookup :: forall s k a . Hashable k => k -> HashMap s k a -> Maybe (Key s k, a)refined-containers Data.HashMap.Refined If the key is in the map, return the proof of this, and the associated value; otherwise return Nothing.
lookup :: forall s k a . Hashable k => k -> HashMap s k a -> Maybe (Key s k, a)refined-containers Data.HashMap.Strict.Refined If the key is in the map, return the proof of this, and the associated value; otherwise return Nothing.