python - 为什么Python中排序列表转换为集合后元素顺序会发生变化？

Question

为什么当我将列表转换为集合时顺序会发生变化？如何在 Python 中获得排序结果？

string = 'test'
result = sorted([character for character in string])
print(result)

#output
['e', 's', 't', 't']

print(set(result))

#output
{'t', 'e', 's'}

我正在尝试制作这个:

{'e', 's', 't'}

Answer 1

根据docs :

A set object is an unordered collection of distinct hashable objects. Common uses include membership testing, removing duplicates from a sequence, and computing mathematical operations such as intersection, union, difference, and symmetric difference.

这里你应该使用:

from collections import OrderedDict
string = 'test'
result = sorted([character for character in string])
print(list(OrderedDict.fromkeys(result)))

或者，如果您的版本 >= 3.7，则字典已排序，因此您可以使用:

string = 'test'
result = sorted([character for character in string])
print(list(dict.fromkeys(result)))