在Python中从csv在字典中创建词典列表

Question

我有一个看起来像这样的csv：

Name;Category;Address
McFood;Fast Food;Street 1
BurgerEmperor;Fast Food;Way 1
BlueFrenchHorn;French;Street 12
PetesPizza;Italian;whatever
SubZero;Fast Food;Highway 6

我想制作一个以类别为键的字典，并以剩余数据作为值的字典列表。所以它看起来像这样：

{'Fast Food' : [{'Name': 'McFood', 'Address': 'Street 1'}, 
                {'Name': 'BurgerEmperor', 'Address': 'Way 1'}],
                ...],
 'French' : [{'Name': 'BlueFrenchHorn', 'Address': 'Street12'}],
...}

（此处缩进以提高可读性）。

我像下面的代码片段一样尝试了一下，但是到那儿我什么也没得到：

import csv
mydict={}

with open ('food.csv', 'r') as csvfile:
        #sniff to find the format
        fileDialect = csv.Sniffer().sniff(csvfile.read(1024))
        csvfile.seek(0)
        #read the CSV file into a dictionary
        dictReader = csv.DictReader(csvfile, dialect=fileDialect)
        for row in dictReader:
            mycategory= row["Category"]
            del row("Category")
            mydict[mycategory]=row

Answer 1

使用collections.defaultdict：

import csv
from collections import defaultdict

mydict = defaultdict(list)  # <---

with open ('food.csv', 'r') as csvfile:
    fileDialect = csv.Sniffer().sniff(csvfile.read(1024))
    csvfile.seek(0)
    dictReader = csv.DictReader(csvfile, dialect=fileDialect)
    for row in dictReader:
        mycategory= row.pop("Category")
        mydict[mycategory].append(row)  # Will put a list for not-existing key

mydict = dict(mydict)  # Convert back to a normal dictionary (optional)