问题描述
测试/检查两个数字是否互为素数（相对素数）的最有效（ pythonic）方法是什么。
What is the most efficient ("pythonic") way to test/check if two numbers are co-primes (relatively prime) in Python.
目前我有这个代码：
def gcd(a, b):
while b != 0:
a, b = b, a % b
return a
def coprime(a, b):
return gcd(a, b) == 1
print(coprime(14,15)) #Should be true
print(coprime(14,28)) #Should be false
可以将用于检查/测试两个数字是否相对质数的代码视为 Pythonic还是有更好的方法？
Can the code for checking/testing if two numbers are relatively prime be considered "Pythonic" or there is some better way?
推荐答案
唯一的改进建议可能是使用函数 gcd 。即，您可以使用以提高速度。
The only suggestion for improvement might be with your function gcd. Namely, you could use gcd that's defined in math (for Python 3.5) for a speed boost.
使用内置版本 gcd 定义 coprime2 ：
from math import gcd as bltin_gcd
def coprime2(a, b):
return bltin_gcd(a, b) == 1
由于以下事实，您几乎将执行速度降低了一半在 C 中实现了 math.gcd （）：
You almost cut down execution speed by half due to the fact that math.gcd is implemented in C (see math_gcd in mathmodule.c):
%timeit coprime(14, 15)
1000000 loops, best of 3: 907 ns per loop
%timeit coprime2(14, 15)
1000000 loops, best of 3: 486 ns per loop
对于Python 您可以使用 fractions.gcd ，但是，正如@ user2357112的注释中所述，它未在 C 中实现。实际上，实际上没有任何动机去使用它，
For Python <= 3.4 you could use fractions.gcd but, as noted in a comment by @user2357112, it is not implemented in C. Actually, there's really no incentive to actually use it, its implementation is exactly the same as yours.
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