python Django 模板：比较 IF 语句中的字典长度
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Django Template: Comparing Dictionary Length in IF Statement
提问by Eldila
I am trying to compare the length of a dictionary inside a django template
我正在尝试比较 django 模板中字典的长度
For example, I would like to know the correct syntax to do the following:
例如，我想知道执行以下操作的正确语法：
{% if error_messages %}
<div class="error">
{% if length(error_messages) > 1 %}
Please fix the following errors:
<div class="erroritem">
{% for key, value in error_messages.items %}
<br>{{ value }}
{% endfor %}
</div>
{% else %}
{% for key, value in error_messages.items %}
{{ value }}
{% endfor %}
{% endif %}
</div>
{% endif %}
回答by Paolo Bergantino
You could do this, using the lengthfilter and the ifequaltag:
{% if error_messages %}
<div class="error">
{% ifequal error_messages|length 1 %}
error_messages[0]
{% else %}
Please fix the following errors:
<div class="erroritem">
{% for key, value in error_messages.items %}
<br>{{ value }}
{% endfor %}
</div>
{% endifequal %}
</div>
{% endif %}
Anything else will have to go down the path of custom tags and filters.
其他任何事情都必须遵循自定义标签和过滤器的路径。
回答by gbozee
You can actually use both the iftag and the lengthfilter
您实际上可以同时使用if标签和 length过滤器
{% if page_detail.page_content|length > 2 %}
<strong><a class="see-more" href="#" data-prevent-default="">
Learn More</a></strong>{% endif %}
NBEnsure no spaces between the dictionary/object and the lengthfilter when used in the iftag so as not to throw an exception.
注意length在if标签中使用时，
确保字典/对象和过滤器之间没有空格，以免引发异常。
回答by zack
use the smart_if template tag:
使用 smart_if 模板标签：
http://www.djangosnippets.org/snippets/1350/
http://www.djangosnippets.org/snippets/1350/
its super cool :)
它超级酷:)
can do all the obvious stuff like:
可以做所有显而易见的事情，比如：
{% if articles|length >= 5 %}...{% endif %}
{% if 文章|长度 >= 5 %}...{% endif %}
{% if "ifnotequal tag" != "beautiful" %}...{% endif %}
{% if "ifnotequal tag" != "beautiful" %}...{% endif %}
