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

Alec的回答很好,但在存在多层嵌套的情况下行不通。下面是一个支持多层嵌套的修改版本。如果嵌套对象已经指定了自己的键(例如Firebase Analytics / BigTable / BigQuery数据),它也会使头名称更好一些:

"""Converts JSON with nested fields into a flattened CSV file.
"""

import sys
import json
import csv
import os

import jsonlines

from orderedset import OrderedSet

# from https://stackoverflow.com/a/28246154/473201
def flattenjson( b, prefix='', delim='/', val=None ):
  if val is None:
    val = {}

  if isinstance( b, dict ):
    for j in b.keys():
      flattenjson(b[j], prefix + delim + j, delim, val)
  elif isinstance( b, list ):
    get = b
    for j in range(len(get)):
      key = str(j)

      # If the nested data contains its own key, use that as the header instead.
      if isinstance( get[j], dict ):
        if 'key' in get[j]:
          key = get[j]['key']

      flattenjson(get[j], prefix + delim + key, delim, val)
  else:
    val[prefix] = b

  return val

def main(argv):
  if len(argv) < 2:
    raise Error('Please specify a JSON file to parse')

  print "Loading and Flattening..."
  filename = argv[1]
  allRows = []
  fieldnames = OrderedSet()
  with jsonlines.open(filename) as reader:
    for obj in reader:
      # print 'orig:\n'
      # print obj
      flattened = flattenjson(obj)
      #print 'keys: %s' % flattened.keys()
      # print 'flattened:\n'
      # print flattened
      fieldnames.update(flattened.keys())
      allRows.append(flattened)

  print "Exporting to CSV..."
  outfilename = filename + '.csv'
  count = 0
  with open(outfilename, 'w') as file:
    csvwriter = csv.DictWriter(file, fieldnames=fieldnames)
    csvwriter.writeheader()
    for obj in allRows:
      # print 'allRows:\n'
      # print obj
      csvwriter.writerow(obj)
      count += 1

  print "Wrote %d rows" % count



if __name__ == '__main__':
  main(sys.argv)

其他回答

这是@MikeRepass回答的修改。此版本将CSV写入文件,适用于Python 2和Python 3。

import csv,json
input_file="data.json"
output_file="data.csv"
with open(input_file) as f:
    content=json.load(f)
try:
    context=open(output_file,'w',newline='') # Python 3
except TypeError:
    context=open(output_file,'wb') # Python 2
with context as file:
    writer=csv.writer(file)
    writer.writerow(content[0].keys()) # header row
    for row in content:
        writer.writerow(row.values())

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。

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()

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

正如在前面的回答中提到的,将json转换为csv的困难在于json文件可以包含嵌套字典,因此是多维数据结构,而csv是2D数据结构。但是,将多维结构转换为csv的一个好方法是使用多个主键连接在一起的csv。

在你的例子中,第一个csv输出的列是“pk”,“model”,“fields”。“pk”和“model”的值很容易获得,但因为“fields”列包含一个字典,它应该是它自己的csv,因为“codename”似乎是主键,你可以使用作为“fields”的输入来完成第一个csv。第二个csv包含来自“fields”列的字典,以codename作为主键,可用于将两个csv绑定在一起。

这是一个解决方案,为您的json文件转换嵌套字典2 csv。

import csv
import json

def readAndWrite(inputFileName, primaryKey=""):
    input = open(inputFileName+".json")
    data = json.load(input)
    input.close()

    header = set()

    if primaryKey != "":
        outputFileName = inputFileName+"-"+primaryKey
        if inputFileName == "data":
            for i in data:
                for j in i["fields"].keys():
                    if j not in header:
                        header.add(j)
    else:
        outputFileName = inputFileName
        for i in data:
            for j in i.keys():
                if j not in header:
                    header.add(j)

    with open(outputFileName+".csv", 'wb') as output_file:
        fieldnames = list(header)
        writer = csv.DictWriter(output_file, fieldnames, delimiter=',', quotechar='"')
        writer.writeheader()
        for x in data:
            row_value = {}
            if primaryKey == "":
                for y in x.keys():
                    yValue = x.get(y)
                    if type(yValue) == int or type(yValue) == bool or type(yValue) == float or type(yValue) == list:
                        row_value[y] = str(yValue).encode('utf8')
                    elif type(yValue) != dict:
                        row_value[y] = yValue.encode('utf8')
                    else:
                        if inputFileName == "data":
                            row_value[y] = yValue["codename"].encode('utf8')
                            readAndWrite(inputFileName, primaryKey="codename")
                writer.writerow(row_value)
            elif primaryKey == "codename":
                for y in x["fields"].keys():
                    yValue = x["fields"].get(y)
                    if type(yValue) == int or type(yValue) == bool or type(yValue) == float or type(yValue) == list:
                        row_value[y] = str(yValue).encode('utf8')
                    elif type(yValue) != dict:
                        row_value[y] = yValue.encode('utf8')
                writer.writerow(row_value)

readAndWrite("data")