Question

如何获得嵌套字典，其中键和子键的顺序正好与csv文件中的顺序相同？

我试过

import csv
from collections import OrderedDict

filename = "test.csv"
aDict = OrderedDict()

with open(filename, 'r') as f:
    csvReader = csv.DictReader(f)
    for row in csvReader:
        key = row.pop("key")
        aDict[key] = row

test.csv看起来像

key,number,letter
eins,1,a
zwei,2,b
drei,3,c

但子词典没有排序（行号和数字都有变化）。那么如何以有序的方式填充aDict[key]？

Answer 1

您必须自己从class ArticleAdmin(admin.ModelAdmin): def save_model(self, request, obj, form, change): if request.user in permited user: obj.save() else: raise forms.ValidationError("you can't do that.")返回的行（而不是使用csv.reader）构建词典和子词典。

幸运的是，这很容易：

csv.DictReader

输出：

import csv
from collections import OrderedDict

filename = 'test.csv'
aDict = OrderedDict()

with open(filename, 'rb') as f:
    csvReader = csv.reader(f)
    fields = next(csvReader)
    for row in csvReader:
        temp = OrderedDict(zip(fields, row))
        key = temp.pop("key")
        aDict[key] = temp

import json  # just to create output
print(json.dumps(aDict, indent=4))

Answer 2

这是一种方式：

import csv
from collections import OrderedDict

filename = "test.csv"
aDict = OrderedDict()

with open(filename, 'r') as f:
    order = next(csv.reader(f))[1:]
    f.seek(0)

    csvReader = csv.DictReader(f)
    for row in csvReader:
        key = row.pop("key")
        aDict[key] = OrderedDict((k, row[k]) for k in order)

Answer 3

csv.DictReader将行加载到常规dict而不是有序行。您必须手动将csv读入OrderedDict才能获得所需的订单：

from collections import OrderedDict

filename = "test.csv"
dictRows = []

with open(filename, 'r') as f:
    rows = (line.strip().split(',') for line in f)
    # read column names from first row
    columns = rows.next()
    for row in rows:
        dictRows.append(OrderedDict(zip(columns, row)))

Answer 4

您可以利用现有的csv.DictReader类，但可以更改它返回的行。为此，请将以下类添加到脚本的开头：

class OrderedDictReader(csv.DictReader):
    def next(self):
        # Get a row using csv.DictReader
        row = csv.DictReader.next(self)

        # Create a new row using OrderedDict
        new_row = OrderedDict(((k, row[k]) for k in self.fieldnames))
        return new_row

然后，使用此类代替csv.DictReader：

csvReader = OrderedDictReader(f)

其余代码保持不变。

如何从csv构建嵌套的有序字典？

4 个答案: