为什么列表操作不返回结果列表? [英] Why don't list operations return the resulting list?

问题描述

我对导致这种情况的思考过程很感兴趣.对我来说，一个相对的新手，它似乎妨碍了，因为它阻止了列表处理的链接"(例如 mylist.reverse().append('a string')[:someLimit]).我想可能是The Powers That Be"认为列表理解是一种更好的范式(有效的意见)，因此不想鼓励其他方法 - 但阻止直觉方法似乎是不正当的，即使更好存在替代方案.

I'm interested in the thought process that led to this. To me, a relative newbie, it seems hampering, since it prevents "chaining" of list processing (e.g. mylist.reverse().append('a string')[:someLimit]). I imagine it might be that "The Powers That Be" decided that list comprehension is a better paradigm (a valid opinion), and so didn't want to encourage other methods - but it seems perverse to prevent an intuitive method, even if better alternatives exist.

请注意，我不是在抱怨(我确定有一个合理的理由，我只是对它是什么感兴趣！)，也不是在寻找解决方案(评论here 非常有启发性)- 只是寻找一些上下文，并更深入地了解语言的设计过程.

Note that I'm not complaining (I'm sure there is a sensible reason, I'm just interested in what it is!), nor looking for a solution (the comments here were very instructive) - just looking for some context, and a deeper understanding of the language's design process.

推荐答案

Python 中的一般设计原则是针对 就地改变对象以返回 None 的函数.我不确定这是否是我选择的设计选择，但基本上是为了强调不返回新对象.

The general design principle in Python is for functions that mutate an object in-place to return None. I'm not sure it would have been the design choice I'd have chosen, but it's basically to emphasise that a new object is not returned.

(GvR(我们的 Python BDFL)在此处说明了设计选择:http://mail.python.org/pipermail/python-dev/2003-October/038855.html)

(GvR's (our Python BDFL) states the design choice here: http://mail.python.org/pipermail/python-dev/2003-October/038855.html)

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