[PYTHON] DJango Memo: From the beginning (creating a view)

Tutorial 3 started. From this time, you will learn how to create a public page.

Write URLConf settings

The following description is required, but it is created automatically at the start project. setting.py ######

ROOT_URLCONF = 'mysite.urls'

The same applies to URLConf in urls.py. First, add a pattern here.

urls.py ######

from django.conf.urls import patterns, include, url  #add to

from django.contrib import admin
admin.autodiscover()

urlpatterns = patterns('',
    # url(r ‘URL pattern’,‘Corresponding view function’)How to write
    url(r'^polls/$', 'polls.views.index'),  #add to
    url(r'^polls/(?P<poll_id>\d+)/$', 'polls.views.detail'),  #add to
    url(r'^polls/(?P<poll_id>\d+)/results/$', 'polls.views.results'),  #add to
    url(r'^polls/(?P<poll_id>\d+)/vote/$', 'polls.views.vote'),  #add to
    url(r'^admin/', include(admin.site.urls))
) 

I googled because I don't understand the regular expression at all.

Basic: http://www.mnet.ne.jp/~nakama/ Python：http://docs.python.jp/2.7/library/re.html#module-re

It seems that ^ means the start point and $ means the end point, so

• **'^ polls $'means "only'polls' is not allowed" (probably) **

As for ‘(? P <poll_id> \ d +)’, if you try to disassemble it from what you know,

• ** () is grouped **

This is used when evaluating multiple characters at once.

• ** Is ‘? P <poll_id>’ like a variable declaration? ** **

It seems that the following corresponding character strings are assigned to poll_id.

• ** ‘\ d’ is half-width 0 to 9 **

It seems that this can also be written as'[0-9]'.

• ** Whether ‘+’ is repeated more than once **

In other words, when it comes to ‘\ d +’ collectively, one or more half-width numbers are applicable.

For the time being, all patterns are changed from ‘^’ to ‘$’, so the expression specified inside it will be excluded.

Make a view

views.py ######

from django.http import HttpResponse

def index(request):  # index.html-like role
    return HttpResponse("Hello, world. You're at the poll index.")

def detail(request, poll_id):  # url:/polls/1/Display with
    return HttpResponse("You're looking at poll %s." % poll_id)
def results(request, poll_id):  # url:/polls/1/results/Display with
    return HttpResponse("You're looking at the results of poll %s." % poll_id)
def vote(request, poll_id):  # url:/polls/1/vote/Display with
    return HttpResponse("You're voting on poll %s." % poll_id)

Functions after detail have poll_id as the first argument. In the previous url (r'URL pattern','view function'), if the URL matches the regular expression, it seems that the value assigned to'? P \ <poll_id>' is passed to the second argument of the view function. (Since they were'\ d +', they are half-width numbers with one or more digits. If it is'url: / pols / 1 /', it is '1'). ** I changed the name and it didn't work, so I may have acquired it as a variable. ** **

When I accessed each URL, it was displayed properly.