Issue with Django Template for loop

Question

so I did some searches but couldn't find the answer to my particular issue... What is happening is that:

I have a model named section which have section_title field. This field can have spaces, for example: "First Section".

When I pass this to Django, I am removing the space in Python with replace(), and created a filter on Django which also removes the space like so:

@register.filter(name='replace_char')
def replace_char(value, arg):
 return value.replace(arg, '')

Then on my template:

{% for subsection in section.section_title|replace_char:" " %}

The issue is that subsection is being shown as each character from section_title, instead of the list that section_title references. Here is the dictionary being passed to the template:

{'sections': [< Section: First Section>, < Section: Second Section>], 'FirstSection': [< Subsection: Subsection 1>, < Subsection: Subsection 2>], 'SecondSection': [< Subsection: Bla1>], 'teste': ['1', '2', '3']}

If I hardcode:

{% for subsection in FirstSection %}

It works...

Any ideas? Thanks!

OBS: I removed the spaces because I thought they were causing the issue, but apparently not. It wasnt working with the spaces as well...

Full template code:

{% for section in sections %}
 <div class="sectionHeader">
 {{ section.section_title }}
 </div>
 <div class="forumSection">
 {% for subsection in section.section_title|replace_char:" " %}
 <div>
 {{ subsection }}
 </div>
 {% endfor %}
 </div>
{% endfor %}

Models:

class Section(models.Model):
 def __str__(self):
 return self.section_title
 section_title = models.CharField(primary_key = True, unique = True, max_length = 50)
class Subsection(models.Model):
 def __str__(self):
 return self.subsection_title
 subsection_title = models.CharField(max_length = 50)
 subsection_section = models.ForeignKey(
 'Section',
 on_delete = models.CASCADE,
 )

• Anup Yadav: I believe what you are following is the only solution.
• GuiFGDeo: @AnupYadav, sorry, I didn't understand what you meant.
• Umar Asghar: can you show what context variable you are passing from your view?
• Kent Shikama: The dictionary being passed to the template doesn't contain "section". Did you mean "sections"?
• GuiFGDeo: @UmarAsghar, isnt the context variable the one in bold on my first comment?

Answer 1

You want to set up a related_name on your foreign key so that you can fetch all your subsections corresponding to the section.

class Section(models.Model):
 section_title = models.CharField(primary_key = True, unique = True, max_length = 50)
class Subsection(models.Model):
 subsection_title = models.CharField(max_length = 50)
 subsection_section = models.ForeignKey(
 'Section',
 related_name = 'subsections',
 on_delete = models.CASCADE,
 )

And then you can change your template code to loop over your subsections as follows:

{% for section in sections %}
 <div class="sectionHeader">
 {{ section.section_title }}
 </div>
 <div class="forumSection">
 <div>
 {% for subsection in section.subsections.all %}
 {{ subsection.subsection_title }}
 {% endfor %}
 </div>
 </div>
{% endfor %}

See https://docs.djangoproject.com/en/1.11/topics/db/queries/#related-objects for more information.

• GuiFGDeo: Yes, I want to do the "unless" portion of your comment. However, section is a foreign_key of subsection, meaning that the section doesnt know which subsections it has... Only subsections knows that it is a child of a given Section... Would I necessarily need to change my models in this case?
• GuiFGDeo: I will add the models to the question description
• Kent Shikama: Hmm sorry I wasn't quite clear. Can you edit your question with the code for the Section model?
• Kent Shikama: Yeah that would be helpful.
• Umar Asghar: @GuiFGDeo use reverse relation in that case. Update the query to cover prefetch_related case as well for bringing the subsections beside sections.