在Python3.7中我们允许如下代码:
>>> dic = [{'one': 1}, {'two': 2}]
>>> for i in dic:
a = [k for k in range(10)]
w = sum([i for i in a])
i['add'] = w
>>> dic
[{'one': 1, 'add': 45}, {'two': 2, 'add': 45}]
没有什么问题，列表生成式中的临时变量的作用域在该列表生成式中，不会与其它变量冲突。
接下来在Python2.7中运行相同的代码：
>>> dic = [{'one': 1}, {'two': 2}]
>>> for i in dic:
... a = [k for k in range(10)]
... w = sum([i for i in a])
... i['add'] = w
...
Traceback (most recent call last):
File "", line 4, in
TypeError: 'int' object does not support item assignment
问题来了这时会出现冲突，导致出现我们不期望的运行结果，需多多注意。
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