从元组列表创建字典，输出错误

Question

countries = [('AGO', 'ANGOLA'), ('PRT', 'PORTUGAL')]

countries_dict = {}
countries_new_list = []
for country_code, country in countries:
    print country_code
    countries_dict['country_code'] = country_code
    countries_new_list.append(countries_dict)

print countries_new_list

此代码将打印

AGO
PRT
[{'country_code': 'PRT'}, {'country_code': 'PRT'}]

我期望的是：

AGO
PRT
[{'country_code': 'AGO'}, {'country_code': 'PRT'}]

我在这里想念什么？

http://codepad.org/nZblGER7

Answer 1

使用列表压缩的 Python方式：-

>>> countries = [('AGO', 'ANGOLA'), ('PRT', 'PORTUGAL')]
>>> [{"country_code":i} for i ,j in countries]
[{'country_code': 'AGO'}, {'country_code': 'PRT'}]
>>> 

Answer 2

我建议你定义词典countries_dict里面的for循环。

countries = [('AGO', 'ANGOLA'), ('PRT', 'PORTUGAL')]
countries_new_list = []
for country_code, country in countries:
    print country_code
    countries_dict = {}
    countries_dict['country_code'] = country_code
    countries_new_list.append(countries_dict)

print countries_new_list

Answer 3

您的错误来自于以下事实：您在countries_dict中附加了字典countries_dict countries_new_list而不是副本。

您应该在for循环中执行countries_dict = {}或使用副本：

from copy import copy
...
countries_new_list.append(copy(countries_dict))