python - 我该如何放置字典 {key : value} in it's designated key in a dictionary so that it is {key: {key: value}} after counting value

Question

我有一个 csv 文件，我正在尝试对 row[3] 进行计数，然后将其与 row[0] 连接

 row[0]      row[3]
 'A01'          'a'
 'B02'          'a'
 'A01'          'b'
 'A01'          'a'
 'B02'          'a'
 'A01'          'a'

所以最后应该是

 {'A01':{a:3, b:1, 'B02':{a,2}}

到目前为止我有这个代码:

d = {'job': {'general_types': 0}}
d['job'] ={}
d['general_types'] ={}
with open("sample.csv", "r") as data1:
    outcome_reader = csv.reader(data1)
    for rows in outcome_reader:
        d['job'].setdefault(rows[0])
        d['general_type'].setdefault(rows[3],0)
        d['general_type'][rows[3]] += 1

目前我收到了 KeyError: 'general_type'

Answer 1

每当您从不存在的字典请求 key 时，都会引发 KeyError。

看起来您将 key 声明为'general_types'，然后通过名称'general_type'请求它。试试这个:

d['general_types'].setdefault(rows[3],0)
d['general_types'][rows[3]] += 1