:: Num a => [a] -> a package:base

The sum function computes the sum of a finite list of numbers.

>>> sum []
0

>>> sum [42]
42

>>> sum [1..10]
55

>>> sum [4.1, 2.0, 1.7]
7.8

>>> sum [1..]
* Hangs forever *

The product function computes the product of a finite list of numbers.

>>> product []
1

>>> product [42]
42

>>> product [1..10]
3628800

>>> product [4.1, 2.0, 1.7]
13.939999999999998

>>> product [1..]
* Hangs forever *

Warning: This is a partial function, it throws an error on empty lists. Use pattern matching, uncons or listToMaybe instead. Consider refactoring to use Data.List.NonEmpty.

Extract the last element of a list, which must be finite and non-empty. WARNING: This function is partial. Consider using unsnoc instead.

Examples

>>> last [1, 2, 3]
3

>>> last [1..]
* Hangs forever *

>>> last []
*** Exception: Prelude.last: empty list