生成器不断返回相同的值 [英] generator keeps returning the same value

问题描述

我被困在这一段代码上，因为我无法让生成器每次调用它时都将下一个值返回给我-它只停留在第一个值上！看看:

I am stuck on this one piece of code because I can't get the generator to return me a the next value every time its called – it just stays on the first one! Take a look:

从numpy导入*

from numpy import *

def ArrayCoords(x,y,RowCount=0,ColumnCount=0):   # I am trying to get it to print
    while RowCount<x:                            # a new coordinate of a matrix
        while ColumnCount<y:                     # left to right up to down each
            yield (RowCount,ColumnCount)         # time it's called.
            ColumnCount+=1
        RowCount+=1
        ColumnCount=0

这就是我得到的:

>>> next(ArrayCoords(20,20))
... (0, 0)
>>> next(ArrayCoords(20,20))
... (0, 0)

但是它只是停留在第一个！我期望这样:

But it's just stuck on the first one! I expected this:

>>> next(ArrayCoords(20,20))
... (0, 0)
>>> next(ArrayCoords(20,20))
... (0, 1)
>>> next(ArrayCoords(20,20))
... (0, 2)

你们能帮我解决代码问题，并解释为什么会这样吗? 预先谢谢你！

Could you guys help me out with the code as well as explain why it is so? Thank you in advance!

推荐答案

每次调用ArrayCoords(20,20)时，它都会返回一个新的生成器对象，该生成器对象与您每调用一次ArrayCoords(20,20)所返回的生成器对象不同.要获得所需的行为，您需要保存生成器:

Each time you call ArrayCoords(20,20) it returns a new generator object, different to the generator objects returned every other time you call ArrayCoords(20,20). To get the behaviour you want, you need to save the generator:

>>> coords = ArrayCoords(20,20)
>>> next(coords)
(0, 0)
>>> next(coords)
(0, 1)
>>> next(coords)
(0, 2)

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