Question

这里我想在嵌套列表的字典中插入一个值。这就是我的尝试，

company_ids = [1,2,3]   
seller_ids = [[0, False, { u'company_id': 4}]]
result = []
for company in company_ids:
    for i in xrange(0, len(seller_ids)):
        seller_ids[i][2]['company_id'] = company
        result.append(seller_ids[i])
print result

我收到了这个

[[0, False, {u'company_id': 3}],
 [0, False, {u'company_id': 3}],
 [0, False, {u'company_id': 3}]]

但我期待这一点，

[[0, False, {u'company_id': 1}],
 [0, False, {u'company_id': 2}],
 [0, False, {u'company_id': 3}]]

请帮我解决这个问题。提前谢谢......

Answer 1

您需要在seller_ids中创建要更改的条目的副本。就像niemmi说的那样，否则你每次都操纵相同的条目。

from copy import deepcopy

company_ids = [1,2,3]   
seller_ids = [[0, False, { u'company_id': 4}]]
result = []
for company in company_ids:
    for i in xrange(0, len(seller_ids)):
        mycopy = deepcopy(seller_ids[i])
        mycopy[2]['company_id'] = company
        result.append(mycopy)

print result

Answer 2

发生这种情况是因为您每次更改并附加相同的列表[0, False, { u'company_id': 4}]到result，所以最后它将包含对最新修改的同一列表的三个引用。

将值插入嵌套列表的dict中

2 个答案: