How do properly make an if statement in html

Question

Im supposed to write an if statement in a detail.html template that states "if project has tasks" display a table otherwise display "no tasks in project. I've tried

{% if task in project %}
{% if task in projects_list %}
{% if tasks in project %}

"displays table"

{% else %}
<p>no tasks for this project</p>
{% endif %}

here is my task model

class Task(models.Model):
    name = models.CharField(max_length=200)
    start_date = models.DateTimeField()
    due_date = models.DateTimeField()
    is_completed = models.BooleanField(default=False)
    project = models.ForeignKey(
        "projects.Project",
        related_name="tasks",
        on_delete=models.CASCADE,
    )
    assignee = models.ForeignKey(
        settings.AUTH_USER_MODEL,
        null=True,
        related_name="tasks",
        on_delete=models.SET_NULL,
    )

    def __str__(self):
        return self.name

    def get_absolute_url(self):
        return reverse("show_my_tasks")

here is the view for projects

class ProjectListView(LoginRequiredMixin, ListView):
    model = Project
    template_name = "projects/list.html"
    context_object_name = "projects_list"

score 0 · Answer 1 · answered Jun 24 '22 at 00:21

0

If project is a list you probably want:

{% if project|length > 0 %}

Similar question Check if an array is not empty in Jinja2

answered Jun 24 '22 at 00:21

Gonzalo Odiard

1,238
12
19

score 0 · Answer 2 · answered Jun 24 '22 at 01:20

0

If I'm understanding correctly, you want to check if a project has any relationship with a task. If this is so, you can refer to the project attribute on the Task model by using the related_name which is tasks in the template. For example:

# using project.tasks to check for an existing relationship with project and task; 
# calling the count method as well to count how many tasks are connected to a project within the loop.
{% if project.tasks.count > 0 %}
     # Displaying the table in here with the project's task info...
{% else %}
     <p> no tasks for this project </p>
{% endif %}

Ideally, your for loop would look something like:

{% for project in projects_list %}
     ...

     {% if project.tasks.count > 0 %}
          # Displaying the table in here with the project's task info...
     {% else %}
          <p> no tasks for this project </p>
     {% endif %}

     ...
{% endfor %}

That should work.

answered Jun 24 '22 at 01:20

Damoiskii

1,328
1
5
20

I tried this but now im getting more errors. Now its no longer even displaying the table or its contents – ImDeez Jun 24 '22 at 01:49
What is the error saying? – Damoiskii Jun 24 '22 at 01:54
Did it display `no tasks for this project` when there are tasks connected to the project? – Damoiskii Jun 24 '22 at 01:55
theyre just assertion errors that say it cannot find the table headers. It just skips past the table and goes to display tasks even tho there are tasks being saved – ImDeez Jun 24 '22 at 02:15
Not sure I'm understanding what you're saying here... "It just skips past the table and goes to display tasks even tho there are tasks being saved". How are you trying to render the task information though? – Damoiskii Jun 24 '22 at 02:55

score 0 · Answer 3 · answered Jun 24 '22 at 08:43

Partial answer, too long to add as a comment. You often don't need to handle the case of an empty list or set outside of the for loop. Instead:

{% for task in project.tasks %}
   {% if forloop.first %}
      <table>  ... and table header
   {% endif %}

    <tr> 
        ... stuff involving display of {{task.field}}s
    </tr>

   {% if forloop.last %}
     </table> ... and any other table footer stuff
   {% endif %}

   {% empty %} ... optional
      stuff to show if there are no tasks

 {% endfor %}

How do properly make an if statement in html

3 Answers3

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