重新整理字典

问题描述

我有一个使用csv.dictwriter读入python的.csv文件，看起来像这样:

I have a .csv file that I've read into python using csv.dictwriter that looks something like this:

[
    {'id':'1', 'date':'12312004','var1':'234', 'var2':'456'},
    {'id':'1', 'date':'12312005','var1':'200', 'var2':'466'},
    {'id':'1', 'date':'12312006','var1':'760', 'var2':'656'},
    {'id':'1', 'date':'12312007','var1':'215', 'var2':'256'},
    {'id':'2', 'date':'5312006','var1':'234', 'var2':'456'},
    {'id':'2', 'date':'5312007','var1':'200', 'var2':'466'},
    {'id':'2', 'date':'5312008','var1':'760', 'var2':'656'},
    {'id':'2', 'date':'5312009','var1':'215', 'var2':'256'},
]

我想将其重组为:

{'1': {
    '12312004': {'var1': '234', 'var2': '456'},
    '12312005': {'var1': '200', 'var2': '466'},
    '12312006': {'var1': '760', 'var2': '656'},
    '12312007': {'var1': '215', 'var2': '256'}},
 '2': {
     '5312006': {'var1': '234', 'var2': '456'},
     '5312007': {'var1': '200', 'var2': '466'},
     '5312008': {'var1': '760', 'var2': '656'},
     '5312009': {'var1': '215', 'var2': '256'}}
}

推荐答案

提供的输入内容是列表，您可以执行以下操作:

Provided your input is a list, you can do this:

output = {}
for entry in input_list:
    entry = entry.copy()  # so we can mangle it
    id = entry.pop('id')
    date = entry.pop('date')
    output.setdefault(id, {})[date] = entry

dict.setdefault()调用返回键id的值，但是如果没有这样的键，则第二个参数将添加到该键的output词典中，并返回.

The dict.setdefault() call returns the value for the key id, but if there is no such key, the second argument will be added to the output dictionary for that key and returned instead.

演示:

>>> input_list = [
...     {'id':'1', 'date':'12312004','var1':'234', 'var2':'456'},
...     {'id':'1', 'date':'12312005','var1':'200', 'var2':'466'},
...     {'id':'1', 'date':'12312006','var1':'760', 'var2':'656'},
...     {'id':'1', 'date':'12312007','var1':'215', 'var2':'256'},
...     {'id':'2', 'date':'5312006','var1':'234', 'var2':'456'},
...     {'id':'2', 'date':'5312007','var1':'200', 'var2':'466'},
...     {'id':'2', 'date':'5312008','var1':'760', 'var2':'656'},
...     {'id':'2', 'date':'5312009','var1':'215', 'var2':'256'},
... ]
>>> output = {}
>>> for entry in input_list:
...     entry = entry.copy()  # so we can alter it
...     id = entry.pop('id')
...     date = entry.pop('date')
...     output.setdefault(id, {})[date] = entry
...
>>> from pprint import pprint
>>> pprint(output)
{'1': {'12312004': {'var1': '234', 'var2': '456'},
       '12312005': {'var1': '200', 'var2': '466'},
       '12312006': {'var1': '760', 'var2': '656'},
       '12312007': {'var1': '215', 'var2': '256'}},
 '2': {'5312006': {'var1': '234', 'var2': '456'},
       '5312007': {'var1': '200', 'var2': '466'},
       '5312008': {'var1': '760', 'var2': '656'},
       '5312009': {'var1': '215', 'var2': '256'}}}

这篇关于重新整理字典的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！