blocks|key|2833044|text|有几种方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|2833045|一种是在正则表达式中使用非捕获组：(?:/(?P<title>[a-zA-Z]%2B)/)?|offset|length|style|CODE|2833046|Making+a+Regex+Django+URL+Token+Optional|2833047|另一种更容易遵循的方法是让多个规则符合您的需求，所有规则都指向相同的视图。|2833048|urlpatterns+=+patterns('',
++++url(r'%5Eproject_config/$',+views.foo),
++++url(r'%5Eproject_config/(?P<product>\w%2B)/$',+views.foo),
++++url(r'%5Eproject_config/(?P<product>\w%2B)/(?P<project_id>\w%2B)/$',+views.foo),
)|code-block|syntax|javascript|2833049|请记住，在您的视图中，您还需要为可选URL参数设置默认值，否则会得到一个错误：|2833050|def+foo(request,+optional_parameter=''):
++++#+Your+code+goes+here|2833051|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/2325433/making-a-regex-django-url-token-optional^0|0|H|R|0|0|14|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|13|8|@$D|14|E|15|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|16|8|@]|9|@$D|17|E|18|1|19]]|A|$]]|$1|J|3|K|5|6|7|1A|8|@]|9|@]|A|$]]|$1|L|3|M|5|N|7|1B|8|@]|9|@]|A|$O|P]]|$1|Q|3|R|5|6|7|1C|8|@]|9|@]|A|$]]|$1|S|3|T|5|N|7|1D|8|@]|9|@]|A|$O|P]]|$1|U|3|-4|5|6|7|1E|8|@]|9|@]|A|$]]]|V|$W|$5|X|Y|Z|A|$10|11]]]]

There are several approaches.

One is to use a non-capturing group in the regex: <code>(?:/(?P&lt;title&gt;[a-zA-Z]+)/)?</code> 
<a href="https://stackoverflow.com/questions/2325433/making-a-regex-django-url-token-optional">Making a Regex Django URL Token Optional</a>

Another, easier to follow way is to have multiple rules that matches your needs, all pointing to the same view.

<pre><code>urlpatterns = patterns('',
 url(r'^project_config/$', views.foo),
 url(r'^project_config/(?P&lt;product&gt;\w+)/$', views.foo),
 url(r'^project_config/(?P&lt;product&gt;\w+)/(?P&lt;project_id&gt;\w+)/$', views.foo),
)
</code></pre>

Keep in mind that in your view you'll also need to set a default for the optional URL parameter, or you'll get an error:

<pre><code>def foo(request, optional_parameter=''):
 # Your code goes here
</code></pre>

blocks|key|203688|text|我想在答案上再加一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|203689|如果您有多个URL定义，则必须分别命名每个URL定义。因此，在调用reverse时，您会失去灵活性，因为一个reverse需要一个参数，而另一个不需要。|203690|使用regex容纳可选参数的另一种方法：|203691|r'%5Eproject_config/(?P<product>\w%2B)/((?P<project_id>\w%2B)/)?$'|code-block|syntax|javascript|203692|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|O|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|P|8|@]|9|@]|A|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Thought I'd add a bit to the answer.

If you have multiple URL definitions then you'll have to name each of them separately. So you lose the flexibility when calling reverse since one reverse will expect a parameter while the other won't.

Another way to use regex to accommodate the optional parameter:

<pre><code>r'^project_config/(?P&lt;product&gt;\w+)/((?P&lt;project_id&gt;\w+)/)?$'
</code></pre>

blocks|key|3045723|text|您可以使用嵌套路由|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3045724|Django+<1.8|3045725|urlpatterns+=+patterns(''
++++url(r'%5Eproject_config/',+include(patterns('',
++++++++url(r'%5E$',+ProjectConfigView.as_view(),+name="project_config")
++++++++url(r'%5E(?P<product>\w%2B)$',+include(patterns('',
++++++++++++url(r'%5E$',+ProductView.as_view(),+name="product"),
++++++++++++url(r'%5E(?P<project_id>\w%2B)$',+ProjectDetailView.as_view(),+name="project_detail")
++++++++))),
++++))),
)|code-block|syntax|javascript|3045726|Django+>=1.8|3045727|urlpatterns+=+[
++++url(r'%5Eproject_config/',+include([
++++++++url(r'%5E$',+ProjectConfigView.as_view(),+name="project_config")
++++++++url(r'%5E(?P<product>\w%2B)$',+include([
++++++++++++url(r'%5E$',+ProductView.as_view(),+name="product"),
++++++++++++url(r'%5E(?P<project_id>\w%2B)$',+ProjectDetailView.as_view(),+name="project_detail")
++++++++])),
++++])),
]|3045728|这要简单得多(假设您想将product+kwarg重命名为product_id，您只需更改第4行，它将影响以下URL。|offset|length|style|CODE|3045729|为Django+1.8及更高版本编辑|3045730|entityMap^0|0|0|0|0|0|C|7|T|A|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|11|8|@$O|12|P|13|Q|R]|$O|14|P|15|Q|R]]|9|@]|A|$]]|$1|S|3|T|5|6|7|16|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|V|$]]

You can use nested routes

Django &lt;1.8

<pre><code>urlpatterns = patterns(''
 url(r'^project_config/', include(patterns('',
 url(r'^$', ProjectConfigView.as_view(), name="project_config")
 url(r'^(?P&lt;product&gt;\w+)$', include(patterns('',
 url(r'^$', ProductView.as_view(), name="product"),
 url(r'^(?P&lt;project_id&gt;\w+)$', ProjectDetailView.as_view(), name="project_detail")
 ))),
 ))),
)
</code></pre>

Django >=1.8

<pre><code>urlpatterns = [
 url(r'^project_config/', include([
 url(r'^$', ProjectConfigView.as_view(), name="project_config")
 url(r'^(?P&lt;product&gt;\w+)$', include([
 url(r'^$', ProductView.as_view(), name="product"),
 url(r'^(?P&lt;project_id&gt;\w+)$', ProjectDetailView.as_view(), name="project_detail")
 ])),
 ])),
]
</code></pre>

This is a lot more DRY (Say you wanted to rename the <code>product</code> kwarg to <code>product_id</code>, you only have to change line 4, and it will affect the below URLs.

Edited for Django 1.8 and above

blocks|key|203729|text|更简单的方法是使用：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|203730|(?P<project_id>\w%2B%7C)|code-block|syntax|javascript|203731|"(a%7Cb)“表示a或b，因此在您的示例中，它可能是一个或多个单词字符(\w%2B)，或者什么都不是。|203732|所以它看起来像这样：|203733|url(
++++r'%5Eproject_config/(?P<product>\w%2B)/(?P<project_id>\w%2B%7C)/$',
++++'tool.views.ProjectConfig',
++++name='project_config'
),|203734|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Q|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|D|7|S|8|@]|9|@]|A|$E|F]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

Even simpler is to use:

<pre><code>(?P&lt;project_id&gt;\w+|)
</code></pre>

The "(a|b)" means a or b, so in your case it would be one or more word characters (\w+) or nothing.

So it would look like:

<pre><code>url(
 r'^project_config/(?P&lt;product&gt;\w+)/(?P&lt;project_id&gt;\w+|)/$',
 'tool.views.ProjectConfig',
 name='project_config'
),
</code></pre>

blocks|key|202032|text|Django+>+2.0版本|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|202033|该方法与Yuji+'Tomita'+Tomita's+Answer中给出的方法基本相同。但是，受影响的是语法：|202034|#+URLconf
...

urlpatterns+=+[
++++path(
++++++++'project_config/<product>/',
++++++++views.get_product,+
++++++++name='project_config'
++++),
++++path(
++++++++'project_config/<product>/<project_id>/',
++++++++views.get_product,
++++++++name='project_config'
++++),
]


#+View+(in+views.py)
def+get_product(request,+product,+project_id='None'):
++++#+Output+the+appropriate+product
++++...|code-block|syntax|javascript|202035|使用path()，您还可以使用类型为dict的可选参数kwargs进行pass+extra+arguments+to+a+view。在这种情况下，您的视图将不需要project_id属性的默认值|CODE|202036|++++...
++++path(
++++++++'project_config/<product>/',
++++++++views.get_product,
++++++++kwargs={'project_id':+None},
++++++++name='project_config'
++++),
++++...|202037|有关如何在最新的Django版本__中执行此操作的信息，请参阅。|202038|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/14351174/1622937|1|https://docs.djangoproject.com/en/dev/ref/urls/#path|2|https://docs.djangoproject.com/en/dev/topics/http/urls/#passing-extra-options-to-view-functions^0|0|E|0|4|T|0|0|0|2|6|I|4|R|6|29|A|2|6|1|Z|U|2|0|0|G|G|0^^$0|@$1|2|3|4|5|6|7|15|8|@$9|16|A|17|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|18|8|@]|D|@$9|19|A|1A|1|1B]]|E|$]]|$1|H|3|I|5|J|7|1C|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|1D|8|@$9|1E|A|1F|B|O]|$9|1G|A|1H|B|O]|$9|1I|A|1J|B|O]|$9|1K|A|1L|B|O]]|D|@$9|1M|A|1N|1|1O]|$9|1P|A|1Q|1|1R]]|E|$]]|$1|P|3|Q|5|J|7|1S|8|@]|D|@]|E|$K|L]]|$1|R|3|S|5|6|7|1T|8|@$9|1U|A|1V|B|C]]|D|@]|E|$]]|$1|T|3|-4|5|6|7|1W|8|@]|D|@]|E|$]]]|U|$V|$5|W|X|Y|E|$Z|10]]|11|$5|W|X|Y|E|$Z|12]]|13|$5|W|X|Y|E|$Z|14]]]]

Django > 2.0 version:

The approach is essentially identical with the one given in <a href="https://stackoverflow.com/a/14351174/1622937">Yuji 'Tomita' Tomita's Answer</a>. Affected, however, is the syntax:

<pre><code># URLconf
...

urlpatterns = [
 path(
 'project_config/&lt;product&gt;/',
 views.get_product, 
 name='project_config'
 ),
 path(
 'project_config/&lt;product&gt;/&lt;project_id&gt;/',
 views.get_product,
 name='project_config'
 ),
]


# View (in views.py)
def get_product(request, product, project_id='None'):
 # Output the appropriate product
 ...
</code></pre>

Using <a href="https://docs.djangoproject.com/en/dev/ref/urls/#path" rel="noreferrer"><code>path()</code></a> you can also <a href="https://docs.djangoproject.com/en/dev/topics/http/urls/#passing-extra-options-to-view-functions" rel="noreferrer">pass extra arguments to a view</a> with the optional argument <code>kwargs</code> that is of type <code>dict</code>. In this case your view would not need a default for the attribute <code>project_id</code>:

<pre><code> ...
 path(
 'project_config/&lt;product&gt;/',
 views.get_product,
 kwargs={'project_id': None},
 name='project_config'
 ),
 ...
</code></pre>

For how this is done in the most recent Django version, see <a href="https://docs.djangoproject.com/en/dev/topics/http/urls/#specifying-defaults-for-view-arguments" rel="noreferrer">the official docs about URL dispatching</a>.

blocks|key|201387|text|Django+=+2.2|type|unstyled|depth|inlineStyleRanges|entityRanges|data|201388|urlpatterns+=+[
++++re_path(r'%5Eproject_config/(?:(?P<product>\w%2B)/(?:(?P<project_id>\w%2B)/)/)?$',+tool.views.ProjectConfig,+name='project_config')
]|code-block|syntax|javascript|201389|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Django = 2.2

<pre><code>urlpatterns = [
 re_path(r'^project_config/(?:(?P&lt;product&gt;\w+)/(?:(?P&lt;project_id&gt;\w+)/)/)?$', tool.views.ProjectConfig, name='project_config')
]
</code></pre>

blocks|key|3045808|text|使用？工作很好，你可以在pythex上查看。记住在视图方法的定义中添加参数*args和**kwargs|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3045809|url('project_config/(?P<product>\w%2B)?(/(?P<project_id>\w%2B/)?)?',+tool.views.ProjectConfig,+name='project_config')|code-block|syntax|javascript|3045810|entityMap|0|LINK|mutability|MUTABLE|url|https://pythex.org/?regex=project_config/(?P%253Cproduct%253E\w%2B)?(/(?P%253Cproject_id%253E\w%2B/)?)?&test_string=project_config/project_config/drink/project_config/drink/12/&ignorecase=0&multiline=0&dotall=0&verbose=0)^0|C|6|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

Use ? work well, you can check on <a href="https://pythex.org/?regex=project_config%2F(%3FP%3Cproduct%3E%5Cw%2B)%3F(%2F(%3FP%3Cproject_id%3E%5Cw%2B%2F)%3F)%3F&amp;test_string=project_config%2F%0Aproject_config%2Fdrink%2F%0Aproject_config%2Fdrink%2F12%2F%0A&amp;ignorecase=0&amp;multiline=0&amp;dotall=0&amp;verbose=0" rel="nofollow noreferrer">pythex</a>. Remember to add the parameters *args and **kwargs in the definition of the view methods

<pre><code>url('project_config/(?P&lt;product&gt;\w+)?(/(?P&lt;project_id&gt;\w+/)?)?', tool.views.ProjectConfig, name='project_config')
</code></pre>

I have a Django URL like this:

<pre><code>url(
 r'^project_config/(?P&lt;product&gt;\w+)/(?P&lt;project_id&gt;\w+)/$',
 'tool.views.ProjectConfig',
 name='project_config'
),
</code></pre>

views.py:

<pre><code>def ProjectConfig(request, product, project_id=None, template_name='project.html'):
 ...
 # do stuff
</code></pre>

The problem is that I want the <code>project_id</code> parameter to be optional.

I want <code>/project_config/</code> and <code>/project_config/12345abdce/</code> to be equally valid URL patterns, so that if <code>project_id</code> is passed, then I can use it.

As it stands at the moment, I get a 404 when I access the URL without the <code>project_id</code> parameter.

Django optional url parameters

路由

Django

我有一个这样的Django URL：url( r'^project_config/(?P<product>\w+)/(?P<project_id>\w+)/$', 'tool.views.ProjectConfig', name='project_config'),views.py:def Proje...

问Django可选url参数
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