Left package:basic-prelude

Left :: a -> Either a b
basic-prelude CorePrelude
lefts :: [Either a b] -> [a]
basic-prelude CorePrelude
Extracts from a list of Either all the Left elements. All the Left elements are extracted in order.

Examples

Basic usage: 
>>> let list = [ Left "foo", Right 3, Left "bar", Right 7, Left "baz" ]

>>> lefts list
["foo","bar","baz"]