Relude.Extra.Foldable1 · relude-1.2.0.0

classclass Foldable f => Foldable1 (f :: Type -> Type) where

The class of foldable data structures that cannot be empty.

Methods

foldMap1 :: Semigroup m => (a -> m) -> f a -> m
Map each element of the non-empty structure to a semigroup, and combine the results.
Example2 expressions
```
>>> foldMap1 SG.Sum (1 :| [2, 3, 4])Sum {getSum = 10}>>> foldMap1 show (123 :| [456, 789, 0])"1234567890"
```

fold1 :: Semigroup m => f m -> m

Combine the elements of a non-empty structure using a semigroup.

Example2 expressions

>>> fold1 (1 :| [2, 3, 4 :: SG.Sum Int])Sum {getSum = 10}>>> fold1 (4 :| [5, 10 :: SG.Product Int])Product {getProduct = 200}

foldr1 :: (a -> b -> b) -> b -> f a -> b
Combines the elements of a non-empty structure using a binary function f.
Example2 expressions
```
>>> foldr1 (+) 0 (1 :| [2, 3])6>>> foldr1 (+) 1 $ Identity 34
```
toNonEmpty :: f a -> NonEmpty a
Convert a non-empty data structure to a NonEmpty list.
Example1 expression
```
>>> toNonEmpty (Identity 2)2 :| []
```
head1 :: f a -> a
The first element of a non-empty data structure.
Example1 expression
```
>>> head1 (1 :| [2, 3, 4])1
```
last1 :: f a -> a
The last element of a non-empty data structure.
Example1 expression
```
>>> last1 (1 :| [2, 3, 4])4
```
maximum1 :: Ord a => f a -> a
The largest element of a non-empty data structure.
Example1 expression
```
>>> maximum1 (32 :| [64, 8, 128, 16])128
```
minimum1 :: Ord a => f a -> a
The smallest element of a non-empty data structure.
Example1 expression
```
>>> minimum1 (32 :| [64, 8, 128, 16])8
```
maximumOn1 :: Ord b => (a -> b) -> f a -> a
The largest element of a non-empty data structure with respect to the given comparison function.
Example1 expression
```
>>> maximumOn1 abs (0 :| [2, 1, -3, -2])-3
```
minimumOn1 :: Ord b => (a -> b) -> f a -> a
The smallest element of a non-empty data structure with respect to the given comparison function.
Example1 expression
```
>>> minimumOn1 abs (0 :| [2, 1, -3, -2])0
```

Instances7Foldable1, …

Foldable1 NonEmptyDefined in relude-1.2.0.0 · Relude.Extra.Foldable1
Foldable1 IdentityDefined in relude-1.2.0.0 · Relude.Extra.Foldable1

IsListError => Foldable1 []Defined in relude-1.2.0.0 · Relude.Extra.Foldable1

⚠️CAUTION⚠️ This instance is for custom error display only.

Foldable1 is not supposed to be used with the lists.

In case it is used by mistake, the user will see the following:

Example1 expression

>>> head1 [1, 2, 3]...... The methods of the 'Foldable1' type class work with non-empty containers.      However, one of the 'Foldable1' functions is applied to the List....      Possible fixes:        * Replace []          with one of the: 'NonEmpty', 'Identity', '(c,)', 'Compose f g', 'Product f g', 'Sum f g'        * Or use 'Foldable' class for your own risk....

Foldable1 (Tuple2 c)Defined in relude-1.2.0.0 · Relude.Extra.Foldable1
(Foldable1 f, Foldable1 g) => Foldable1 (Product f g)Defined in relude-1.2.0.0 · Relude.Extra.Foldable1
(Foldable1 f, Foldable1 g) => Foldable1 (Sum f g)Defined in relude-1.2.0.0 · Relude.Extra.Foldable1
(Foldable1 f, Foldable1 g) => Foldable1 (Compose f g)Defined in relude-1.2.0.0 · Relude.Extra.Foldable1

valuefoldl1' :: (a -> a -> a) -> NonEmpty a -> a

#

Strictly folds non-empty structure with given function f:

foldl1' f [x0, x1, x2 ...] = f (f x0 x1) x2 ...

Example1 expression

>>> foldl1' (++) ([1,2] :| [[3,4], [5,6]])[1,2,3,4,5,6]

valueaverage1 :: (Foldable1 f, Fractional a) => f a -> a

#

Given a Foldable1 of Fractional elements, computes the average if possible and returns the resulting element.

Example2 expressions

>>> average1 (42 :| [])42.0>>> average1 (1 :| [2,3,4])2.5