DA.NonEmpty¶
Type and functions for non-empty lists. This module re-exports many functions with
the same name as prelude list functions, so it is expected to import the module qualified.
For example, with the following import list you will have access to the NonEmpty type
and any functions on non-empty lists will be qualified, for example as NE.append, NE.map, NE.foldl:
import DA.NonEmpty (NonEmpty)
import qualified DA.NonEmpty as NE
Functions¶
- nonEmpty
: [a] -> Optional (NonEmpty a)
Turn a list into a non-empty list, if possible. Returns
Noneif the input list is empty, andSomeotherwise.
- deleteBy
: (a -> a -> Bool) -> a -> NonEmpty a -> [a]
The ‘deleteBy’ function behaves like ‘delete’, but takes a user-supplied equality predicate.
- delete
: Eq a => a -> NonEmpty a -> [a]
Remove the first occurence of x from the non-empty list, potentially removing all elements.
- foldl1
: (a -> a -> a) -> NonEmpty a -> a
Apply a function repeatedly to pairs of elements from a non-empty list, from the left. For example,
foldl1 (+) (NonEmpty 1 [2,3,4]) = ((1 + 2) + 3) + 4.
- foldr1
: (a -> a -> a) -> NonEmpty a -> a
Apply a function repeatedly to pairs of elements from a non-empty list, from the right. For example,
foldr1 (+) (NonEmpty 1 [2,3,4]) = 1 + (2 + (3 + 4)).
- foldr
: (a -> b -> b) -> b -> NonEmpty a -> b
Apply a function repeatedly to pairs of elements from a non-empty list, from the right, with a given initial value. For example,
foldr (+) 0 (NonEmpty 1 [2,3,4]) = 1 + (2 + (3 + (4 + 0))).
- foldrA
: Action m => (a -> b -> m b) -> b -> NonEmpty a -> m b
The same as
foldrbut running an action each time.
- foldr1A
: Action m => (a -> a -> m a) -> NonEmpty a -> m a
The same as
foldr1but running an action each time.
- foldl
: (b -> a -> b) -> b -> NonEmpty a -> b
Apply a function repeatedly to pairs of elements from a non-empty list, from the left, with a given initial value. For example,
foldl (+) 0 (NonEmpty 1 [2,3,4]) = (((0 + 1) + 2) + 3) + 4.