在 Python 中，什么决定了遍历 kwargs 时的顺序? [英] In Python, what determines the order while iterating through kwargs?

问题描述

在 python 中，我编写了这个函数来自学 **kwargs 在 Python 中的工作原理:

In python, I wrote this function to teach myself how **kwargs works in Python:

def fxn(a1, **kwargs):
    print a1
    for k in kwargs:
        print k, " : ", kwargs[k]

然后我用

fxn(3, a2=2, a3=3, a4=4)

这是我的 Python 解释器打印的输出:

Here was the output that my Python interpreter printed:

3
a3  :  3
a2  :  2
a4  :  4

为什么即使我先将 a2 输入到我的函数中，for 循环也会在 a2 之前打印 a3 的值?

Why did the for loop print the value of a3 before that of a2 even though I fed a2 into my function first?

推荐答案

kwargs 是一本字典.字典是无序的 - 简单地说，顺序是未指定的，并且是一个实现细节.深入了解会发现顺序会因项目的哈希值、插入顺序等而有很大差异，因此您最好不要依赖任何与之相关的内容.

kwargs is a dictionary. Dictionaries are unordered - simply put, the order is unspecified and an implementation detail. Peeking under the hood will show that the order varies wildly depending on the hash values of the items, the order of insertion, etc. so you better don't rely on anything related to it.

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