Django2.1 include()函數報錯'provide the namespace argument to include() instead.' % len(arg)

《Python編程：從入門到實踐》項目三 Web應用程序

書中原來的程序

from django.conf.urls import include, url
from django.contrib import admin

urlpatterns = [
    url(r'^admin/', include(admin.site.urls)),
    url(r'', include('learning_logs.urls', namespace='learning_logs')),
]

在Terminal中運行：

(ll_env) F:\Python\pycharm-workspace\learning_log>python manage.py runserver

 運行報錯：

File "F:\Python\pycharm-workspace\learning_log\lear
ning_log\urls.py", line 22, in <module>
    url(r'^admin/', include(admin.site.urls)),
  File "F:\Python\pycharm-workspace\learning_log\ll_e
nv\lib\site-packages\django\urls\conf.py", line 27, in include
    'provide the namespace argument to include() instead.' % len(arg)
django.core.exceptions.ImproperlyConfigured: Passing a 3-tuple to include() is not supported. Pass a 2-tuple containing the list of patterns and app_name, and provide
 the namespace argument to include() instead.

 修改：

from django.conf.urls import include, url
from django.contrib import admin

urlpatterns = [
    url(r'^admin/', admin.site.urls),# 不用include()函數
    url(r'', include(('learning_logs.urls','learning_logs'), namespace='learning_logs')),
    # url(r'', include('learning_logs.urls')), # 或者修改爲include(pattern_list)這種用法也是可以的！！！
]

 報錯原因如下：

 最後查找資料，Django2.1的官方文檔。

 

根據文檔的提示，admin.site.urls不用include()函數。書中第二個include()函數沒有提供app_namespace，所以會報錯！

修改好就可以正常運行了！