2017年StackOverflow上最好的20个Python问题

Myth丶恋晨 2022-05-31 22:57 241阅读 0赞

1、Python的 .. (点号 点号) 是什么语法？

答案地址：[https://stackoverflow.com/questions/43487811/what-is-python-dot-dot-notation-syntax][https_stackoverflow.com_questions_43487811_what-is-python-dot-dot-notation-syntax]

2、为什么在Python3中 x\*\*4.0 比 x\*\*4运行的快？

答案地址：[https://stackoverflow.com/questions/42355194/why-is-x4-0-faster-than-x4-in-python-3][https_stackoverflow.com_questions_42355194_why-is-x4-0-faster-than-x4-in-python-3]

3、给定一个长度为100万的数字（比如π），写代码计算出所有连续的三个数字，且要求该连续的三个数字至少重复出现过一次。

答案地址：[https://stackoverflow.com/questions/47581326/given-a-string-of-a-million-numbers-return-all-repeating-3-digit-numbers][https_stackoverflow.com_questions_47581326_given-a-string-of-a-million-numbers-return-all-repeating-3-digit-numbers]

4、为什么在Python中表达式 0, 0 == (0, False) 的结果是 (0, False)

答案地址：[https://stackoverflow.com/questions/44864156/why-in-python-0-0-0-0-equals-0-false][https_stackoverflow.com_questions_44864156_why-in-python-0-0-0-0-equals-0-false]

5、Python会把一个只用做返回值的变量优化掉吗？

答案地址：[https://stackoverflow.com/questions/43390869/does-python-optimize-away-a-variable-thats-only-used-as-a-return-value][https_stackoverflow.com_questions_43390869_does-python-optimize-away-a-variable-thats-only-used-as-a-return-value]

6、加速Python3中百万次级的正则替换。

答案地址：[https://stackoverflow.com/questions/42742810/speed-up-millions-of-regex-replacements-in-python-3][https_stackoverflow.com_questions_42742810_speed-up-millions-of-regex-replacements-in-python-3]

7、两个集合做并集，为什么会丢失集合中的元素？

答案地址：[https://stackoverflow.com/questions/44489658/union-of-2-sets-does-not-contain-all-items][https_stackoverflow.com_questions_44489658_union-of-2-sets-does-not-contain-all-items]

8、在for循环中，i = i + 1 和 i += 1有什么区别？

答案地址：[https://stackoverflow.com/questions/41446833/what-is-the-difference-between-i-i-1-and-i-1-in-a-for-loop][https_stackoverflow.com_questions_41446833_what-is-the-difference-between-i-i-1-and-i-1-in-a-for-loop]

9、为什么拷贝一个洗牌过的列表要慢很多？

答案地址：[https://stackoverflow.com/questions/42107442/why-is-copying-a-shuffled-list-much-slower][https_stackoverflow.com_questions_42107442_why-is-copying-a-shuffled-list-much-slower]

10、为什么元组比列表消耗更少的内存？

答案地址：[https://stackoverflow.com/questions/46664007/why-do-tuples-take-less-space-in-memory-than-lists][https_stackoverflow.com_questions_46664007_why-do-tuples-take-less-space-in-memory-than-lists]

11、在Python中，当你用一个变量给另外一个变量赋值时，发生了什么？

答案地址：[https://stackoverflow.com/questions/45053461/what-happens-when-you-assign-the-value-of-one-variable-to-another-variable-in-py][https_stackoverflow.com_questions_45053461_what-happens-when-you-assign-the-value-of-one-variable-to-another-variable-in-py]

12、为什么这个Python字符串尝试转换为整数失败后，连大小都变了。

答案地址：[https://stackoverflow.com/questions/47062184/why-does-the-size-of-this-python-string-change-on-a-failed-int-conversion][https_stackoverflow.com_questions_47062184_why-does-the-size-of-this-python-string-change-on-a-failed-int-conversion]

13、如何判断一个列表是否能被另一个列表整除？

答案地址：[https://stackoverflow.com/questions/45906747/is-a-list-potentially-divisible-by-another][https_stackoverflow.com_questions_45906747_is-a-list-potentially-divisible-by-another]

14、理解语句 \*x ,= list。

答案地址：[https://stackoverflow.com/questions/43190992/understanding-x-lst][https_stackoverflow.com_questions_43190992_understanding-x-lst]

15、为什么for循环中可以使用任意目标表达式？

答案地址：[https://stackoverflow.com/questions/44317993/why-are-arbitrary-target-expressions-allowed-in-for-loops][https_stackoverflow.com_questions_44317993_why-are-arbitrary-target-expressions-allowed-in-for-loops]

16、更好的 Python for 循环方式。

答案地址：[https://stackoverflow.com/questions/46996315/a-better-way-for-a-python-for-loop][https_stackoverflow.com_questions_46996315_a-better-way-for-a-python-for-loop]

17、Python and操作符的奇怪的使用方式。

答案地址：[https://stackoverflow.com/questions/47007680/strange-use-of-pythons-and-operator][https_stackoverflow.com_questions_47007680_strange-use-of-pythons-and-operator]

18、增加Python代码逻辑层数的上限个数。

答案地址：[https://stackoverflow.com/questions/44972719/why-does-python-have-a-limit-on-the-number-of-static-blocks-that-can-be-nested][https_stackoverflow.com_questions_44972719_why-does-python-have-a-limit-on-the-number-of-static-blocks-that-can-be-nested]

19、如何让一个dataframe围着中心旋转？

答案地址：[https://stackoverflow.com/questions/47152691/how-to-pivot-a-dataframe][https_stackoverflow.com_questions_47152691_how-to-pivot-a-dataframe]

20、把一个变量赋值给自己，这有什么用？

答案地址：[https://stackoverflow.com/questions/43853407/re-assigning-a-name-to-itself][https_stackoverflow.com_questions_43853407_re-assigning-a-name-to-itself]

转载自python程序员公众号

[https_stackoverflow.com_questions_43487811_what-is-python-dot-dot-notation-syntax]: https://stackoverflow.com/questions/43487811/what-is-python-dot-dot-notation-syntax
[https_stackoverflow.com_questions_42355194_why-is-x4-0-faster-than-x4-in-python-3]: https://stackoverflow.com/questions/42355194/why-is-x4-0-faster-than-x4-in-python-3
[https_stackoverflow.com_questions_47581326_given-a-string-of-a-million-numbers-return-all-repeating-3-digit-numbers]: https://stackoverflow.com/questions/47581326/given-a-string-of-a-million-numbers-return-all-repeating-3-digit-numbers
[https_stackoverflow.com_questions_44864156_why-in-python-0-0-0-0-equals-0-false]: https://stackoverflow.com/questions/44864156/why-in-python-0-0-0-0-equals-0-false
[https_stackoverflow.com_questions_43390869_does-python-optimize-away-a-variable-thats-only-used-as-a-return-value]: https://stackoverflow.com/questions/43390869/does-python-optimize-away-a-variable-thats-only-used-as-a-return-value
[https_stackoverflow.com_questions_42742810_speed-up-millions-of-regex-replacements-in-python-3]: https://stackoverflow.com/questions/42742810/speed-up-millions-of-regex-replacements-in-python-3
[https_stackoverflow.com_questions_44489658_union-of-2-sets-does-not-contain-all-items]: https://stackoverflow.com/questions/44489658/union-of-2-sets-does-not-contain-all-items
[https_stackoverflow.com_questions_41446833_what-is-the-difference-between-i-i-1-and-i-1-in-a-for-loop]: https://stackoverflow.com/questions/41446833/what-is-the-difference-between-i-i-1-and-i-1-in-a-for-loop
[https_stackoverflow.com_questions_42107442_why-is-copying-a-shuffled-list-much-slower]: https://stackoverflow.com/questions/42107442/why-is-copying-a-shuffled-list-much-slower
[https_stackoverflow.com_questions_46664007_why-do-tuples-take-less-space-in-memory-than-lists]: https://stackoverflow.com/questions/46664007/why-do-tuples-take-less-space-in-memory-than-lists
[https_stackoverflow.com_questions_45053461_what-happens-when-you-assign-the-value-of-one-variable-to-another-variable-in-py]: https://stackoverflow.com/questions/45053461/what-happens-when-you-assign-the-value-of-one-variable-to-another-variable-in-py
[https_stackoverflow.com_questions_47062184_why-does-the-size-of-this-python-string-change-on-a-failed-int-conversion]: https://stackoverflow.com/questions/47062184/why-does-the-size-of-this-python-string-change-on-a-failed-int-conversion
[https_stackoverflow.com_questions_45906747_is-a-list-potentially-divisible-by-another]: https://stackoverflow.com/questions/45906747/is-a-list-potentially-divisible-by-another
[https_stackoverflow.com_questions_43190992_understanding-x-lst]: https://stackoverflow.com/questions/43190992/understanding-x-lst
[https_stackoverflow.com_questions_44317993_why-are-arbitrary-target-expressions-allowed-in-for-loops]: https://stackoverflow.com/questions/44317993/why-are-arbitrary-target-expressions-allowed-in-for-loops
[https_stackoverflow.com_questions_46996315_a-better-way-for-a-python-for-loop]: https://stackoverflow.com/questions/46996315/a-better-way-for-a-python-for-loop
[https_stackoverflow.com_questions_47007680_strange-use-of-pythons-and-operator]: https://stackoverflow.com/questions/47007680/strange-use-of-pythons-and-operator
[https_stackoverflow.com_questions_44972719_why-does-python-have-a-limit-on-the-number-of-static-blocks-that-can-be-nested]: https://stackoverflow.com/questions/44972719/why-does-python-have-a-limit-on-the-number-of-static-blocks-that-can-be-nested
[https_stackoverflow.com_questions_47152691_how-to-pivot-a-dataframe]: https://stackoverflow.com/questions/47152691/how-to-pivot-a-dataframe
[https_stackoverflow.com_questions_43853407_re-assigning-a-name-to-itself]: https://stackoverflow.com/questions/43853407/re-assigning-a-name-to-itself