如何在Jinja python的for循环中添加变量

Question

I am trying to loop over a product list{more so a queryset} in django using for loop, by adding the range of products The following code works when printed out in cmd prompt

for card in allproduct[nextRangePage:limit]:
    print(card.name)

But the Jinja pattern fails for some reason

{% for card in product[{%'nextRangePage'%}:{%'limit'%}] %}

The error is

django.template.exceptions.TemplateSyntaxError: Could not parse the remainder: '[{%'nextRangePage'' from 'allproduct[{%'nextRangePage''

The context variables are:

context = {
'product': product_list,
'pages': pages,
'nextRangePage': nextRangePage,
}

[product_list = allproduct]

Answer 1

You never nest Jinja {{...}} or {%...%} markers. Instead of:

{% for card in product[{%'nextRangePage'%}:{%'limit'%}] %}

You need:

{% for card in product[nextRangePage:limit] %}

For example, given the following code:

import jinja2

product = [{'name': f'item{i}'} for i in range(10)]

t = jinja2.Template('''
{% for card in product[nextRangePage:limit] %}
{{ card }}
{% endfor %}
''')

print(t.render(product=product, nextRangePage=2, limit=8))

The output is:

{'name': 'item2'}

{'name': 'item3'}

{'name': 'item4'}

{'name': 'item5'}

{'name': 'item6'}

{'name': 'item7'}