python之学习Django，却对变量一头雾水

我正在学习 Django 教程，我正处于创建投票应用程序的第 3 步。有一个名为“question_id”的变量，我无法理解它的确切定义或来源。我将在下面发布文件。我唯一的猜测是，当在 Models.py 中定义类问题时，这个变量是由 Django 在内部以某种方式创建的，但我不确定。它没有在“问题”类中定义。

这是我的文件:

View .py

from django.shortcuts import render 
from django.http import HttpResponse 
from django.template import loader 
 
from .models import Question 
 
 
def index(request): 
    latest_question_list = Question.objects.order_by('-pub_date')[:5] 
    context = {'latest_question_list': latest_question_list} 
    return render(request, 'polls/index.html', context) 
 
 
#def index(request): 
#    return HttpResponse("Hello, world. You're at the polls index.") 
 
def detail(request, question_id): 
    return HttpResponse("You're looking at question %s." % question_id) 
 
def results(request, question_id): 
    response = "Your looking at result of question %s." 
    return HttpResponse(response % question_id) 
 
def vote(reqeust, question_id): 
    return HttpResponse("You're voting on question %s." % question_id) 

网址.py

from django.conf.urls import url 
 
from . import views 
 
urlpatterns = [ 
    #ex: /polls/ 
    url(r'^$', views.index, name='index'), 
    #ex: /polls/5 
    url(r'^(?P<question_id>[0-9]+/$)', views.detail, name='detail'), 
    #ex: /polls/5/result/ 
    url(r'^(?P<question_id>[0-9]+/results/$)', views.results, name='results'), 
    #ex: /polls/5/vote 
    url(r'^(?P<question_id>[0-9]+/vote/$)', views.vote, name='vote'), 
] 

模型.py

import datetime 
 
from django.db import models 
from django.utils import timezone 
 
 
class Question(models.Model): 
    question_text = models.CharField(max_length=200) 
    pub_date = models.DateTimeField('date published') 
 
    def __str__(self): 
        return self.question_text 
 
    def was_published_recently(self): 
        return self.pub_date >= timezone.now() - datetime.timedelta(days=1) 
 
 
 
class Choice(models.Model): 
    question = models.ForeignKey(Question, on_delete=models.CASCADE) 
    choice_text = models.CharField(max_length=200) 
    votes = models.IntegerField(default=0) 
 
    def __str__(self): 
        return self.choice_text 

谢谢你的帮助， 内敏

请您参考如下方法:

显示的三个 View 中的question_id 是由django 自动创建的。为此，它将 url 作为输入。在这里定义

url(r'^(?P<question_id>[0-9]+/$)', views.detail, name='detail'), 

因此，如果您在浏览器中输入 polls/somenumber/，您的名为 detail 的 View 将传递一个名为 question_id 的变量和一个值一些

urls.py 中使用的正则表达式确保这是一个数字而不是其他东西。

有关更多信息，请参阅:https://docs.djangoproject.com/en/1.10/topics/http/urls/