我有一个JSON文件,我想转换为CSV文件。我如何用Python做到这一点?

我试着:

import json
import csv

f = open('data.json')
data = json.load(f)
f.close()

f = open('data.csv')
csv_file = csv.writer(f)
for item in data:
    csv_file.writerow(item)

f.close()

然而,这并没有起作用。我正在使用Django和我收到的错误是:

`file' object has no attribute 'writerow'`

然后我尝试了以下方法:

import json
import csv

f = open('data.json')
data = json.load(f)
f.close()

f = open('data.csv')
csv_file = csv.writer(f)
for item in data:
    f.writerow(item)  # ← changed

f.close()

然后得到错误:

`sequence expected`

样本json文件:

[{
        "pk": 22,
        "model": "auth.permission",
        "fields": {
            "codename": "add_logentry",
            "name": "Can add log entry",
            "content_type": 8
        }
    }, {
        "pk": 23,
        "model": "auth.permission",
        "fields": {
            "codename": "change_logentry",
            "name": "Can change log entry",
            "content_type": 8
        }
    }, {
        "pk": 24,
        "model": "auth.permission",
        "fields": {
            "codename": "delete_logentry",
            "name": "Can delete log entry",
            "content_type": 8
        }
    }, {
        "pk": 4,
        "model": "auth.permission",
        "fields": {
            "codename": "add_group",
            "name": "Can add group",
            "content_type": 2
        }
    }, {
        "pk": 10,
        "model": "auth.permission",
        "fields": {
            "codename": "add_message",
            "name": "Can add message",
            "content_type": 4
        }
    }
]

当前回答

首先,JSON包含嵌套对象,因此通常不能直接转换为CSV。你需要把它改成这样:

{
    "pk": 22,
    "model": "auth.permission",
    "codename": "add_logentry",
    "content_type": 8,
    "name": "Can add log entry"
},
......]

下面是我的代码来生成CSV:

import csv
import json

x = """[
    {
        "pk": 22,
        "model": "auth.permission",
        "fields": {
            "codename": "add_logentry",
            "name": "Can add log entry",
            "content_type": 8
        }
    },
    {
        "pk": 23,
        "model": "auth.permission",
        "fields": {
            "codename": "change_logentry",
            "name": "Can change log entry",
            "content_type": 8
        }
    },
    {
        "pk": 24,
        "model": "auth.permission",
        "fields": {
            "codename": "delete_logentry",
            "name": "Can delete log entry",
            "content_type": 8
        }
    }
]"""

x = json.loads(x)

f = csv.writer(open("test.csv", "wb+"))

# Write CSV Header, If you dont need that, remove this line
f.writerow(["pk", "model", "codename", "name", "content_type"])

for x in x:
    f.writerow([x["pk"],
                x["model"],
                x["fields"]["codename"],
                x["fields"]["name"],
                x["fields"]["content_type"]])

你会得到如下输出:

pk,model,codename,name,content_type
22,auth.permission,add_logentry,Can add log entry,8
23,auth.permission,change_logentry,Can change log entry,8
24,auth.permission,delete_logentry,Can delete log entry,8

其他回答

此代码适用于任何给定的json文件

# -*- coding: utf-8 -*-
"""
Created on Mon Jun 17 20:35:35 2019
author: Ram
"""

import json
import csv

with open("file1.json") as file:
    data = json.load(file)



# create the csv writer object
pt_data1 = open('pt_data1.csv', 'w')
csvwriter = csv.writer(pt_data1)

count = 0

for pt in data:

      if count == 0:

             header = pt.keys()

             csvwriter.writerow(header)

             count += 1

      csvwriter.writerow(pt.values())

pt_data1.close()

修改了Alec McGail的答案,以支持包含列表的JSON

    def flattenjson(self, mp, delim="|"):
            ret = []
            if isinstance(mp, dict):
                    for k in mp.keys():
                            csvs = self.flattenjson(mp[k], delim)
                            for csv in csvs:
                                    ret.append(k + delim + csv)
            elif isinstance(mp, list):
                    for k in mp:
                            csvs = self.flattenjson(k, delim)
                            for csv in csvs:
                                    ret.append(csv)
            else:
                    ret.append(mp)

            return ret

谢谢!

由于数据看起来是字典格式,因此似乎应该实际使用csv.DictWriter()来实际输出带有适当标题信息的行。这将使转换更容易处理。然后fieldnames参数将正确地设置顺序,而第一行的输出作为标题将允许稍后由csv.DictReader()读取和处理。

例如,Mike Repass使用

output = csv.writer(sys.stdout)

output.writerow(data[0].keys())  # header row

for row in data:
  output.writerow(row.values())

不过,只需将初始设置更改为 输出= csv。DictWriter数据(文件集,字段名= [0]. keys ())

注意,由于字典中元素的顺序没有定义,您可能必须显式地创建字段名条目。一旦你这样做了,writerow就可以工作了。然后写操作就像最初显示的那样工作。

使用pandas库,这就像使用两个命令一样简单!

df = pd.read_json()

read_json将JSON字符串转换为pandas对象(序列或数据帧)。然后:

df.to_csv()

它既可以返回字符串,也可以直接写入csv文件。请参阅to_csv的文档。

根据之前的冗长回答,我们都应该感谢熊猫提供的这条捷径。

关于非结构化JSON,请参阅这个答案。

编辑: 有人问我一个最小的例子:

import pandas as pd

with open('jsonfile.json', encoding='utf-8') as inputfile:
    df = pd.read_json(inputfile)

df.to_csv('csvfile.csv', encoding='utf-8', index=False)

令人惊讶的是,我发现到目前为止贴在这里的答案都没有正确处理所有可能的场景(例如,嵌套字典,嵌套列表,无值等)。

这个解决方案应该适用于所有场景:

def flatten_json(json):
    def process_value(keys, value, flattened):
        if isinstance(value, dict):
            for key in value.keys():
                process_value(keys + [key], value[key], flattened)
        elif isinstance(value, list):
            for idx, v in enumerate(value):
                process_value(keys + [str(idx)], v, flattened)
        else:
            flattened['__'.join(keys)] = value

    flattened = {}
    for key in json.keys():
        process_value([key], json[key], flattened)
    return flattened