如何在json文件中寫入我的數據？

Question

如何在json文件中寫入我的數據？這是我的嘗試：

from django.test import TestCase 
from django_dynamic_fixture import G 
import content.factories 
from django.core import serializers 
from content.models import UserProfile, Delivery 
from django.contrib.auth.models import User 

class DeliveryTest(TestCase): 
    def test_sample_data(self): 
     for i in range(0,10): 
      user = content.factories.UserFactory.create() 
      print user 
      for j in range(0, 50): 
       delivery = content.factories.DeliveryFactory.create(user=user) 
       print delivery 

       with open("file.json", "w") as out: 
        data = serializers.serialize("json", User.objects.all()) 

       with open("file.json", "w") as out: 
        data2 = serializers.serialize("json", Delivery.objects.all()) 

輸出（打印）：http://dpaste.com/hold/923339/

Answer 1

你實際上並沒有寫你的數據，只能轉換成JSON。在打開的文件調用.write()：

with open("file.json", "w") as out: 
    data = serializers.serialize("json", User.objects.all()) 
    out.write(data) 
    data2 = serializers.serialize("json", Delivery.objects.all()) 
    out.write(data) 

只有開放file.json一次;每當您打開它以使用'w'模式進行書寫時，它將首先被擦除。

另外，get a reference to the serializer並告訴它來寫，直接打開文件：

with open("file.json", "w") as out: 
    json_serializer = serializers.get_serializer('json')() 
    json_serializer.serialize(User.objects.all(), stream=out) 
    json_serializer.serialize(Delivery.objects.all(), stream=out) 

這是更有效的。