可能重复: What is :: (double colon) in Python?
我读了问题What is :: (double colon) in Python when subscripting sequences?,但这不能回答myarray [x :: y]的意思。
它打印列表/数组中的每个第y个元素
>>> a = [1,2,3,4,5,6,7,8,9] >>> a[::3] [1, 4, 7]
[x :: y]的附加语法意味着从位置x开始获取每个第y个元素
即。
>>> a[2::3] [3, 6, 9]