izip不工作在Python 3.x [英] izip not working in Python 3.x

问题描述

我要导入izip模块，像这样：

I am trying to import the izip module like so:

from itertools import izip

但是最近从Python 2.7转换到3之后，它似乎无法正常工作。

However after recently changing over from Python 2.7 to 3 - it doesn't seem to work.

我试图写一个csv文件：

I am trying to write to a csv file:

writer.writerows(izip(variable1,2))

但我没有运气。仍然遇到错误。

But I have no luck. Still encounter an error.

推荐答案

在oython3中，内置的 zip 与2.X中的 izip 相同的工作（返回一个生成器而不是列表），但是稍快一些，因为它是一个内置函数。

In oython3 the built in zip does the same job as izip in 2.X (returns a generator instead of a list) but slightly faster as it's a built-in function.

这里是python 2和3中的 zip 之间的一个长凳;在python 2中的 izip

Here is a benchmarck between zip in python 2 and 3 and izip in python 2:

Pyhon 2.7：

Pyhon 2.7:

In [5]: %timeit list(izip(range(100), range(100)))
100000 loops, best of 3: 5.16 µs per loop

In [6]: %timeit zip(range(100), range(100))
100000 loops, best of 3: 3.87 µs per loop

python 3：

In [2]: %timeit list(zip(range(100), range(100)))
100000 loops, best of 3: 3.84 µs per loop

在这种情况下，因为 zip 的参数必须支持迭代，你不能使用2作为其参数。所以如果你想写一个csv行2变量，你可以把它们放在一个元组或列表：

In this case since zip's arguments must support iteration you can not use 2 as its argument.So if you want to write 2 variable as a csv row you can put them in a tuple or list :

writer.writerows((variable1,2))

也可以从 itertools 导入 zip_longest 你可以在不同大小的迭代器上使用它。

Also from itertools you can import zip_longest as a more flexible function which you can use it on iterators with different size.

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