Python 将 csv.DictReader 对象转换为字典列表？

Convert a csv.DictReader object to a list of dictionaries?

提问by Tim

A csv file names.csvhas content:

一个 csv 文件names.csv包含以下内容：

first_name last_name
Baked Beans
Lovely Spam
Wonderful Spam

I would like to read it into a list of dictionaries, with the first row containing the keys:

我想将它读入字典列表，第一行包含键：

>>> import csv
>>> with open('names.csv') as csvfile:
...     reader = csv.DictReader(csvfile)
...     for row in reader:
...         print(row['first_name'], row['last_name'])
...
Baked Beans
Lovely Spam
Wonderful Spam

But is the type of readercsv.DictReader? How can I convert readerinto a list of dictionaries? Thanks.

但类型是readercsv.DictReader? 如何转换reader为字典列表？谢谢。

回答by alecxe

Use list():

使用list()：

print(list(reader))

Demo:

演示：

>>> with open('names.csv') as csvfile:
...     reader = csv.DictReader(csvfile, delimiter=" ")
...     print(list(reader))
... 
[{'first_name': 'Baked', 'last_name': 'Beans'}, {'first_name': 'Lovely', 'last_name': 'Spam'}, {'first_name': 'Wonderful', 'last_name': 'Spam'}]

回答by Padraic Cunningham

import csv
with open("in.csv") as csvfile:
    reader = csv.DictReader(csvfile,delimiter=" ")
    print(list(reader))
[{'first_name': 'Baked', 'last_name': 'Beans'}, {'first_name': 'Lovely', 'last_name': 'Spam'}, {'first_name': 'Wonderful', 'last_name': 'Spam'}]

If the delimiter is not actually a ,you need to specify " "or whatever it is.

如果分隔符实际上不是 a,您需要指定" "或无论如何。

Just to clear any confusion, the code works fine for python3.6 also, the only difference is that using DictReadergives Orderdictsby default:

为了消除任何混淆，该代码也适用于 python3.6，唯一的区别是使用DictReader默认提供Orderdicts：

In [1]: import csv
   ...: with open("in.csv") as csvfile:
   ...:     reader = csv.DictReader(csvfile, delimiter=" ")
   ...:     print(list(reader))
   ...:     
[OrderedDict([('first_name', 'Baked'), ('last_name', 'Beans')]), OrderedDict([('first_name', 'Lovely'), ('last_name', 'Spam')]), OrderedDict([('first_name', 'Wonderful'), ('last_name', 'Spam')])]

You can access keys exactly the same, an OrderedDictjust keeps key insertion order:

您可以完全相同地访问密钥，OrderedDict只是保持密钥插入顺序：

In [2]: import csv
   ...: with open("in.csv") as csvfile:
   ...:     reader = csv.DictReader(csvfile, delimiter=" ")
   ...:     for dct in reader:
   ...:         print(f"{dct['first_name']} {dct['last_name']}")
   ...:         
   ...:     
Baked Beans
Lovely Spam
Wonderful Spam

Which py3.6 actually does too, so if for some reason you really want a dict:

哪个 py3.6 实际上也是如此，所以如果由于某种原因你真的想要一个 dict：

In [5]: import csv
   ...: with open("in.csv") as csvfile:
   ...:     reader = csv.DictReader(csvfile, delimiter=" ")
   ...:     for dct in map(dict, reader):
   ...:         print(dct)
   ...:         print(f"{dct['first_name']} {dct['last_name']}")
   ...:         
   ...:     
{'first_name': 'Baked', 'last_name': 'Beans'}
Baked Beans
{'first_name': 'Lovely', 'last_name': 'Spam'}
Lovely Spam
{'first_name': 'Wonderful', 'last_name': 'Spam'}
Wonderful Spam

The ordering retention on insertion in py3.6 is an implementation detailand may change, but if enough of us use it, it may just have to stay :)

py3.6 中插入时的排序保留是一个实现细节，可能会改变，但如果我们有足够多的人使用它，它可能只需要保留 :)

回答by Exebit

Create function

创建函数

import csv


def csv_to_dict(filename):
    result_list=[]
    with open(filename) as file_obj:
        reader = csv.DictReader(file_obj, delimiter=delimiter)
        for row in reader:
            result_list.append(dict(row))
    return result_list

and use it:

并使用它：

list_of_dicts = csv_to_dict('names.csv')

回答by Ninga

The csv.DictReader creates a dictreader object as noted in the title. This object is only useable while the file is open and cant be sliced.

csv.DictReader 创建一个 dictreader 对象，如标题中所述。此对象仅在文件打开且无法切片时可用。

To convert the object to a list as per the title....

要根据标题将对象转换为列表....

list_of_dicts = list(your_dictreader_object)