这是什么意思? [英] What does [:] mean?

问题描述

我正在分析一些Python代码，但不知道什么

I'm analyzing some Python code and I don't know what

pop = population[:]

表示.是Java中的数组列表还是二维数组?

means. Is it something like array lists in Java or like a bi-dimensional array?

推荐答案

这是切片符号的示例，其作用取决于population的类型.如果population是列表，则此行将创建浅拷贝.对于类型为tuple或str的对象，它将不执行任何操作(如果不使用[:]，则行将执行相同操作)，对于(例如)NumPy数组，它将为相同的数据创建一个新视图

It is an example of slice notation, and what it does depends on the type of population. If population is a list, this line will create a shallow copy of the list. For an object of type tuple or a str, it will do nothing (the line will do the same without [:]), and for a (say) NumPy array, it will create a new view to the same data.

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