Is it possible to project the second argument of the inner function when mapping across a set of items in Python?
when using map with the monadic use of the int cast function it works simply:
list(map(int, ["4","3","1","2"]))
But I want to cast multiple binary digits to an int using int's dyadic form int("1101",2) using map:
list(map(int(,2), ["1101","0001","1100","0011"]))
you need lambda
list(map(lambda x : int(x,2), ["1101","0001","1100","0011"]))
but when you need list, lambda and map, that's a dead giveaway that you just need list comprehension:
[int(x,2) for x in ["1101","0001","1100","0011"]]
(clearer, shorter, and faster than map when lambda is required)
The int function has signature:
int(x, base=10)
So we can make a partial, where we assign base=2 to:
from functools import partial
list(map(partial(int, base=2), ["1101","0001","1100","0011"]))partial takes as first parameter a function (here int) as well as other (named and unnamed) parameters. It constructs a function that will fill in some parameters itself.
functools.partial. +1If you need to pass arguments to int, you'll need to wrap it in a function. You can use a normal function:
def func(i):
return int(i, 2)
Or you can use a lambda function definition instead:
lambda i: int(i, 2)
Your code would then be:
list(map(lambda i: int(i, 2), ["1101","0001","1100","0011"]))However, as @Jean said, once you reach this point, you should seriously consider using a comprehension over map and lambda.
