Assign multiple functions to a single variable?

Question

In Python we can assign a function to a variable. For example, the math.sine function:

sin = math.sin
rad = math.radians
print sin(rad(my_number_in_degrees))         


        

Answer 1

You could write a helper function to perform the function composition for you and use it to create the kind of variable you want. Some nice features are that it can combine a variable number of functions together that each accept a variable number of arguments.

import math
try:
    reduce
except NameError:  # Python 3
    from functools import reduce

def compose(*funcs):
    """ Compose a group of functions (f(g(h(...)))) into a single composite func. """
    return reduce(lambda f, g: lambda *args, **kwargs: f(g(*args, **kwargs)), funcs)

sindeg = compose(math.sin, math.radians)

print(sindeg(90))  # -> 1.0