如何用 Python 的“范围”按二数计算

How to count by twos with Python's 'range'

提问by J. C. Rocamonde

So imagine I want to go over a loop from 0 to 100, but skipping the odd numbers (so going "two by two").

所以想象一下，我想遍历一个从 0 到 100 的循环，但跳过奇数（所以要“两个两个”）。

for x in range(0,100):
    if x%2 == 0:
        print x

This fixes it. But imagine I want to do so jumping two numbers? And what about three? Isn't there a way?

这修复了它。但是想象一下，我想要跳两个数字吗？那么三个呢？没有办法吗？

采纳答案by Jivan

Use the step argument (the last, optional):

使用 step 参数（最后一个，可选）：

for x in range(0, 100, 2):
    print(x)

Note that if you actually want to keepthe odd numbers, it becomes:

请注意，如果您确实想保留奇数，则变为：

for x in range(1, 100, 2):
    print(x)

Rangeis a verypowerfulfeature.

范围是一个非常强大的功能。

回答by ZdaR

(Applicable to Python <= 2.7.x only)

（仅适用于 Python <= 2.7.x）

In some cases, if you don't want to allocate the memory to a list then you can simply use the xrange() function instead of the range() function. It will also produce the same results, but its implementation is a bit faster.

在某些情况下，如果您不想将内存分配给列表，那么您可以简单地使用 xrange() 函数而不是 range() 函数。它也会产生相同的结果，但它的实现速度要快一些。

for x in xrange(0,100,2):
    print x,   #For printing in a line

>>> 0, 2, 4, ...., 98 

Python 3actually made rangebehave like xrange, which doesn't exist anymore.

Python 3实际上使range行为类似于xrange，它不再存在。

回答by Secret Name

for i in range(0, 100, 2):
    print i

If you are using an IDE, it tells you syntax:

如果您使用的是IDE，它会告诉您语法：

min, max, step(optional)

最小、最大、步长（可选）