30-seconds-of-code/snippets/python/s/compose-right.md

title, type, language, tags, cover, dateModified

title	type	language	tags	cover	dateModified
Reverse compose functions	snippet	python	function	lavender-shelf	2020-11-02T19:27:07+02:00

Performs left-to-right function composition.

• Use functools.reduce() to perform left-to-right function composition.
• The first (leftmost) function can accept one or more arguments; the remaining functions must be unary.

from functools import reduce

def compose_right(*fns):
  return reduce(lambda f, g: lambda *args: g(f(*args)), fns)

add = lambda x, y: x + y
square = lambda x: x * x
add_and_square = compose_right(add, square)
add_and_square(1, 2) # 9