test_list = []
dic1 = {}
test_list = [dic1 for _ in range(3)]
ll = [1, 2, 3]
for i in range(3):
test_list[i]['value'] = ll[i]
print(test_list)
运行结果:每次赋值都更改了所有项
原因:python的二位数据创建方式就是这样,官方文档中有描述What has happened is that [[]] is a one-element list containing an empty list,
so all thr服务器托管网ee elements of [[]] * 3 are references to this single empty list.
Modifying any of the elements of lists modifies this single list. You can create a list of different lists this way:
>>> lists = [[] for i in range(3)]
>>> lists[0].append(3)
>>> lists[1].append(5)
>>> lists[2].append(7)
>>> lists
[[3], [5], [7]]
那么,将上述代码修改为:
test_list = []
test_list = [{} for _ in range(3)]
ll = [1, 2, 3]
for i in range(3):
test_list[i]['value'] = ll[i]
print(test_list)
结果正确:
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