Python 3范围与Python 2范围 [英] Python 3 range Vs Python 2 range

问题描述

我最近开始学习python3.
在 python 2 中，range()函数可用于分配列表元素.

I recently started learning python 3.
In python 2 range() function can be used to assign list elements.

>>> A = []
>>> A = range(0,6)
>>> print A
[0, 1, 2, 3, 4, 5]

在 python 3 中，当使用range()函数时，这种情况正在发生

where as in python 3 when range() function is used this is happening

>>> A = []
>>> A = range(0,6)
>>> print(A)
range(0, 6)

为什么会这样?
python为什么要进行此更改?
是恩赐还是祸根?

why is this happening?
why did python do this change?
Is it a boon or a bane ?

推荐答案

Python 3 使用 iterators 进行很多操作，其中 python 2 列表.文档提供了详细说明，包括更改为range.

Python 3 uses iterators for a lot of things where python 2 used lists.The docs give a detailed explanation including the change to range.

优点在于，如果您使用的是大范围迭代器或映射，则 Python 3 不需要分配内存. 例如

The advantage is that Python 3 doesn't need to allocate the memory if you're using a large range iterator or mapping. For example

for i in range(1000000000): print(i)

在python 3中需要少得多的内存. 如果您确实想让Python一次全部展开列表，则可以

requires a lot less memory in python 3. If you do happen to want Python to expand out the list all at once you can

list_of_range = list(range(10))

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