如何访问Django模板forloop中的下一个和上一个元素? [英] How to access the next and the previous elements in a Django template forloop?
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问题描述
在Django forloop中获取上一个和下一个元素的最佳方法是什么?我正在打印元素列表,并希望子元素位于div块中.所以我想要这样的东西:
What is the best way to get previous and next elements in Django forloop? I'm printing a list of elements and want child element to be in div-block. So I want something like this:
{% for element in list %}
{% if element.is_child and not list[forloop.counter-1].is_child %}
<div class="children-block">
{% endif %}
{{ element.title }}
{% if element.is_child and not list[forloop.counter+1].is_child %}
</div>
{% endif %}
{% endfor %}
您可以看到我的问题是 list [forloop.counter-1]
.我该怎么办?
As you can see my problem is list[forloop.counter-1]
. How can I do it?
推荐答案
You can create custom template filters next
and previous
which returns the next and the previous elements of the for
loop respectively.
from django import template
register = template.Library()
@register.filter
def next(some_list, current_index):
"""
Returns the next element of the list using the current index if it exists.
Otherwise returns an empty string.
"""
try:
return some_list[int(current_index) + 1] # access the next element
except:
return '' # return empty string in case of exception
@register.filter
def previous(some_list, current_index):
"""
Returns the previous element of the list using the current index if it exists.
Otherwise returns an empty string.
"""
try:
return some_list[int(current_index) - 1] # access the previous element
except:
return '' # return empty string in case of exception
然后,您可以在模板中执行以下操作以访问下一个和上一个元素.
Then in your template you can do the following to access the next and previous elements.
{% with next_element=some_list|next:forloop.counter0 %} # assign next element to a variable
{% with previous_element=some_list|previous:forloop.counter0 %} # assign previous element to a variable
最终密码:
{% for element in list %}
{% with next_element=list|next:forloop.counter0 %} # get the next element
{% with previous_element=list|previous:forloop.counter0 %} # get the previous element
{% if element.is_child and not previous_element.is_child %}
<div class="children-block">
{% endif %}
{{ element.title }}
{% if element.is_child and not next_element.is_child %}
</div>
{% endif %}
{% endwith %}
{% endwith %}
{% endfor %}
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