Django rest framework Django Rest框架：serializer.data在shell中显示{}

serializer.data在python shell中显示{}。但有四个实例具有一定的价值。当我运行django项目时，它会显示[{}，{}，{}，{}]。为什么？ 我将遵循，我正在ubuntu 16.04中运行我的项目

这是我的密码

教程/settings.py

INSTALLED_APPS = [
'django.contrib.admin',
'django.contrib.auth',
'django.contrib.contenttypes',
'django.contrib.sessions',
'django.contrib.messages',
'django.contrib.staticfiles',
'rest_framework',
'snippets.apps.SnippetsConfig',

]

snippets/models.py

from django.db import models
from pygments.lexers import get_all_lexers
from pygments.styles import get_all_styles

LEXERS = [item for item in get_all_lexers() if item[1]]
LANGUAGE_CHOICES = sorted([(item[1][0], item[0]) for item in LEXERS])
STYLE_CHOICES = sorted((item, item) for item in get_all_styles())


class Snippet(models.Model):
created = models.DateTimeField(auto_now_add=True)
title = models.CharField(max_length=100, blank=True, default='')
code = models.TextField()
linenos = models.BooleanField(default=False)
language = models.CharField(choices=LANGUAGE_CHOICES, default='python', max_length=100)
style = models.CharField(choices=STYLE_CHOICES, default='friendly', max_length=100)

class Meta:
    ordering = ('created',)

序列化程序.py

from rest_framework import serializers
from snippets.models import Snippet, LANGUAGE_CHOICES, STYLE_CHOICES


class SnippetSerializer(serializers.Serializer):
class Meta:
    model = Snippet
    fields = ('id', 'title', 'code', 'linenos', 'language', 'style')
def create(self, validated_data):
    """
    Create and return a new `Snippet` instance, given the validated data.
    """
    return Snippet.objects.create(**validated_data)

def update(self, instance, validated_data):
    """
    Update and return an existing `Snippet` instance, given the validated data.
    """
    instance.title = validated_data.get('title', instance.title)
    instance.code = validated_data.get('code', instance.code)
    instance.linenos = validated_data.get('linenos', instance.linenos)
    instance.language = validated_data.get('language', instance.language)
    instance.style = validated_data.get('style', instance.style)
    instance.save()
    return instance

snippets/url.py

from django.conf.urls import url
from snippets import views

urlpatterns = [
url(r'^snippets/$', views.snippet_list),
url(r'^snippets/(?P<pk>[0-9]+)/$', views.snippet_detail),

从django.conf.url导入url
从代码段导入视图
URL模式=[
url（r“^snippets/$”，视图。代码段列表），
url（r“^snippets/（？P[0-9]+）/$”，视图。snippet\u详细信息），

---

]

请您编写代码好吗？我已经添加了代码。请检查它。还要编写视图类。重要的是，我认为在pythodshell中调用代码段详细视图，在浏览器中调用代码段列表视图。请注意这些图案。它与这两个url有一点不同。