This seems such a simple thing but I can't seem to get it to work for one, and two I can't seem to be getting a straight forward answer online on wether it can or can't be done.
I just want a simple tag that will work like so
{% if my_tag %}
render something
{% else %}
render something else
{% endif %}
now I don't care about filters or any other ways you might be able to do the same thing, I want it to look exactly like that, and work like described, I have a simple tag made that actually does return True or False as needed, and it's called if I call the tag like this
{% my_tag %}
however it does't get called if I add an if in front of the tag, is a feature this simple and logical not implemented?
Like the link to the potential duplicate states, you can use an assignment tag similar to the following that will return the current time:
#register.assignment_tag
def get_current_time(format_string):
return datetime.datetime.now().strftime(format_string)
Within your template you can then do what you are desiring to do:
{% if get_current_time %}
...show time
{% else %}
...don't show time
{% endif %}
Related
Currently I display a link to my sites homepage in the base template using this code :
{% if page.slug != 'homepage' %}
<!-- insert link code here -->
{% endif %}
However I like to reuse my code and sometimes the page is called something else. What I would like to write is something like :
{% if page != request.site.root_page %}
However this does not work, although if I display the values of these fields in the template they are both equal or not as expected ...
<p>{{ request.site.root_page }} and {{ page }}<p>
Results in :
<p>Contact and Contact</p> # On the root page
or
<p>Contact and Test</p> # On a different page
The opposite problem to this as the data is not specific to one page, but to every page except one.
What am I missing?
Okay in the process of explaining the question, I also found the answer. It doesn't work (I believe) because although these values look the same, they are actually objects with different properties, therefore the comparison fails.
In order for the comparison to succeed you need to extract values from each object and compare them. So this will not work ...
{% if page != request.site.root_page %}
However both of these do work ...
{% if page.title != request.site.root_page.title %}
... or ...
{% if page.url != request.site.root_page.url %}
Kicking myself now, but hopefully my public humiliation will help someone in the future.
I am very new to django and working on it.. I visited a html file and dont know the difference between {{}} and {% %} in html files used
as here
{% load static %}
Thanks a lot
You can use
{% %} For sentences such as if and for or to call tags such as load, static, etc.
{{ }} To render variables in the template.
Read More about it at Django Docs
{% %} is for displaying code and {{}} is for displaying variables
There are three things in the template in Django
First is template variable and the second thing is template tag and third and last is template filter
so we write a template variable is {{}}
and write a template tag is {% %}
third and last is template filter {{variable |filter:arg}}
I'm new too for Django, so if i'm wrong, please someone correct me.
The difference between they are:
{{variable}} is used to use a variables. When the template encounters a variable, it evaluates that variable and replaces it with the result.
You also can use filters {{variable|filter}} like this:
{{name|length}} in this case you will use a variable "name" and return the length of that variable.
{%tag%} could use for loops or logic, or load external information into the template to be used by later variables. You can create block tags to help extend other html files parts. Also you can create custom tags.
A good place to see how to do it:
https://www.codementor.io/hiteshgarg14/creating-custom-template-tags-in-django-application-58wvmqm5f
Tags like loops and block, need to be closed.
{% %} for IF ELSE CONDITIONS and FOR LOOP etc
{{ }} for veriables that rendered from view function also used in FOR LOOP veriables like
`enter code here`
{% for obj in qs%}
{{ obj.veriable_name }}
{% endfor %}
Seems like elementary question, and yet can't get it work
{% if iterator.next > 10 %}
Do smth
{% endif %}
Two issues. First, this code just won't work (the code in the if-condition never implemented even when the condition seems to hold true), and second issue - the ">" sign is highlighted as if it where the closing tag of the closest open tag. Any ideas how to fix the first issue and is it all right with second issues ? Maybe there's some elegant syntax that I am missing and that would remove this ambiguity for the text editor ?
iterator.next may be a string which would result in the statement being False.
Try creating a custom filter to convert it to an int. For example create "my_filters.py":
# templatetags/my_filters.py
from django import template
register = template.Library()
#register.filter()
def to_int(value):
return int(value)
Then in your template:
{% load my_filters %}
{% if iterator.next|to_int > 10 %}
Do smth
{% endif %}
More on custom tags and filters here
I wouldn't worry about the highlighting, this may just be your IDE. I recommend using PyCharm for Django development
Django's docs says that you can use > with if tag:
{% if somevar < 100 %}
This appears if variable somevar is less than 100.
{% endif %}
take a look at documentation: https://docs.djangoproject.com/en/1.9/ref/templates/builtins/
maybe you are missing something else?
I have an issue. I've written a custom template tag with a function signature like this-
def has_paid_for_article(article, request):
Now, in my template tag I have a conditional statement to determine whether a user can download an article or not (this is determined by if the article is older than two years or the logged in user has paid for the article). Here's the snippet-
{% if article|is_older_than_two_years %}
<span class="amp">& </span>{% get_article_download_link article %}
{% else %}
download
{% endif %}
The aforementioned snippet works fine, however I need to call the has_paid_for_article() function inside of a conditional statement. I've tried the following ways to make this happen-
{% if article|is_older_than_two_years or article|request|has_paid_for_article %}
,
{% if article|is_older_than_two_years or [article, request]|has_paid_for_article %}
This one works outside of the conditional statement-
{% if article|is_older_than_two_years or has_paid_for_article article request %}
What would be the correct syntax here? Also, I've read other posts on the topic, I CANNOT put this logic in the view. I won't go into detail, but with the way it works, that is not an option. Thank you!
Try
{% if article|is_older_than_two_years or article|has_paid_for_article:request %}
See Writing custom template filters
This seems to me like a very simple question, but I can't seem to find the answer.
All I need to do is determine the number of objects returned by a database query.
The specific circumstance is this: I have a model named Student. This model has a ManyToManyField member named courses_current, which relates to a table of Course models. When I pass my Student instance to a template, I want to be able to do something like the following (the syntax may not be exact, but you'll get the basic idea):
<div id="classes">
{% if student.classes_current.all.size == 0 %}
<h1> HEY! YOU AREN'T TAKING ANY CLASSES! REGISTER NOW!
{% else %}
Here are your courses:
<!-- ... -->
{% endif %}
</div>
Now, I'm fairly certain that X_set.all.size is not a real thing. In the manage.py shell I can just use len(student.classes_current.all()), but I don't know of any way to use built-in functions, and "dictionary-like objects" don't have .size() functions, so I'm at a loss. I'm sure there's a very simple solution (or at least I hope there is), but I can't seem to find it.
{{ student.classes_current.all.count }} but be warned that it doesn't fetch the objects so you will need to do a separate query if you want to loop over them.
If you need loop over the classes for tag has way to get what you need.
{% for cl in student.current_classes.all %}
{{ cl }}
{% empty %}
<h1>Hey! ...</h1>
{% endfor %}
Documentation https://docs.djangoproject.com/en/dev/ref/templates/builtins/?from=olddocs#for-empty