Using * idiom to unpack arguments when using map()

Question

Is there a way to unpack a tuple with the * idiom when using the map built-in in Python?

Ideally, I'd like to do the following:

def foo(a, b):
  return a**2 + b

x = [(1,2), (3,4), (5,6)]

results = map(foo, *x)

where results would equal [3, 13, 31]

Answer 1

You're looking for itertools.starmap:

def foo(a, b):
  return a**2 + b

x = [(1,2), (3,4), (5,6)]

from itertools import starmap

starmap(foo, x)
Out[3]: <itertools.starmap at 0x7f40a8c99310>

list(starmap(foo, x))
Out[4]: [3, 13, 31]

Note that even in python 2, starmap returns an iterable that you have to manually consume with something like list.

Answer 2

An uglier way than the @roippi's way...

x = [(1,2), (3,4), (5,6)]

map(lambda y:y[0]**2 + y[1], x)