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

我已经尝试了很多建议的解决方案(也熊猫没有正确地规范化我的JSON),但真正好的是正确解析JSON数据来自Max Berman。

我写了一个改进,以避免每一行都有新列 在解析期间将其放置到现有列。 如果只有一个数据存在,则将值存储为字符串,如果该列有更多值,则将值存储为列表。

它有一个输入。Json文件作为输入,并输出一个output.csv。

import json
import pandas as pd

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, v, flattened)
                # process_value(keys + [str(idx)], v, flattened)
        else:
            key1 = '__'.join(keys)
            if not flattened.get(key1) is None:
                if isinstance(flattened[key1], list):
                    flattened[key1] = flattened[key1] + [value]
                else:
                    flattened[key1] = [flattened[key1]] + [value]
            else:
                flattened[key1] = value

    flattened = {}
    for key in json.keys():
        k = key
        # print("Key: " + k)
        process_value([key], json[key], flattened)
    return flattened

try:
    f = open("input.json", "r")
except:
    pass
y = json.loads(f.read())
flat = flatten_json(y)
text = json.dumps(flat)
df = pd.read_json(text)
df.to_csv('output.csv', index=False, encoding='utf-8')

其他回答

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)

如果我们考虑下面的例子,将json格式的文件转换为csv格式的文件。

{
 "item_data" : [
      {
        "item": "10023456",
        "class": "100",
        "subclass": "123"
      }
      ]
}

下面的代码将转换json文件(data3. xml)。Json)转换为CSV文件(data3.csv)。

import json
import csv
with open("/Users/Desktop/json/data3.json") as file:
    data = json.load(file)
    file.close()
    print(data)

fname = "/Users/Desktop/json/data3.csv"

with open(fname, "w", newline='') as file:
    csv_file = csv.writer(file)
    csv_file.writerow(['dept',
                       'class',
                       'subclass'])
    for item in data["item_data"]:
         csv_file.writerow([item.get('item_data').get('dept'),
                            item.get('item_data').get('class'),
                            item.get('item_data').get('subclass')])

上面提到的代码已经在本地安装的pycharm中执行,它已经成功地将json文件转换为csv文件。希望这有助于转换文件。

使用csv.DictWriter()很容易,详细的实现可以像这样:

def read_json(filename):
    return json.loads(open(filename).read())
def write_csv(data,filename):
    with open(filename, 'w+') as outf:
        writer = csv.DictWriter(outf, data[0].keys())
        writer.writeheader()
        for row in data:
            writer.writerow(row)
# implement
write_csv(read_json('test.json'), 'output.csv')

注意,这假设所有JSON对象都具有相同的字段。

这是一份可能对你有帮助的参考资料。

import json,csv
t=''
t=(type('a'))
json_data = []
data = None
write_header = True
item_keys = []
try:
with open('kk.json') as json_file:
    json_data = json_file.read()

    data = json.loads(json_data)
except Exception as e:
    print( e)

with open('bar.csv', 'at') as csv_file:
    writer = csv.writer(csv_file)#, quoting=csv.QUOTE_MINIMAL)
    for item in data:
        item_values = []
        for key in item:
            if write_header:
                item_keys.append(key)
            value = item.get(key, '')
            if (type(value)==t):
                item_values.append(value.encode('utf-8'))
            else:
                item_values.append(value)
        if write_header:
            writer.writerow(item_keys)
            write_header = False
        writer.writerow(item_values)

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