python列表:append vs + = [英] python list: append vs +=
问题描述
对于Python列表， append()是否与 + = 相同?我知道 + 会导致创建新列表，而 append()只是将新内容附加到旧列表中.但是，是否会优化 + = 以使其更类似于 append()?因为他们做同样的事情.
For Python list, is append() the same as +=?
I know that + will lead to the creation of a new list, while append() just append new stuff to the old list.
But will += be optimized to be more similar to append()? since they do the same thing.
推荐答案
它是 __ iadd __ 运算符.文档.
重要的是，这意味着仅重试即可添加.例如，如果x是具有 __ iadd __()方法的类的实例，则 x + = y 等效于 x = x .__ iadd __(y)，否则，将考虑 x .__ add __(y)和 y .__ radd __(x)，与对 x + y ."
Importantly, this means that it only tries to append. "For instance, if x is an instance of a class with an __iadd__() method, x += y is equivalent to x = x.__iadd__(y) . Otherwise, x.__add__(y) and y.__radd__(x) are considered, as with the evaluation of x + y."
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