[Python] Converting a string of integers to a list of int - performance [duplicate]

Given a string S of whitespace delimited integers and needing to convert to a list of int, there are 2 common techniques.

lst = list(map(int, S.split())) # method 1


or

lst = [int(n) for n in S.split()] # method 2


To my surprise, I found that method 1 is faster than method 2 by a factor of ~9% (which I would argue is significant) whereas I would have expected little or no difference.

Can someone please explain why method 1 is, apparently, more performant?

Here's the test rig:

from timeit import timeit
from random import randint

R = (1, 100_000)
N = 10_000

SNUMS = " ".join(str(randint(*R)) for _ in range(N))

def pdiff(v1: float, v2: float) -> float:
return (v1 - v2) / ((v1 + v2) / 2) * 100.

def func1() -> list[int]:
return list(map(int, SNUMS.split()))

def func2() -> list[int]:
return [int(n) for n in SNUMS.split()]

assert func1() == func2()

dx = (0.0, 0.0)

for func in (func1, func2):
d = timeit(lambda: func(), number=N)
dx = (dx[1], d)
print(func.__name__, f"{d:.4f}s")

print(f"{pdiff(*dx):.2f}%")


Output:

func1 5.5540s
func2 6.0766s
-8.99%


Platform:

Python 3.13.3
MacOS 15.4.1
Apple M2

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