问题描述
如何在列表的第一个索引处插入元素?如果我使用 list.insert(0, elem),elem 会修改第一个索引的内容吗?还是我必须用第一个元素创建一个新列表,然后将旧列表复制到这个新列表中?
How can I insert an element at the first index of a list? If I use list.insert(0, elem), does elem modify the content of the first index? Or do I have to create a new list with the first elem and then copy the old list inside this new one?
推荐答案
使用insert:
In [1]: ls = [1,2,3] In [2]: ls.insert(0, "new") In [3]: ls Out[3]: ['new', 1, 2, 3]