I've got a Django template I'd sometimes like to pass a list and sometimes like to pass a single value. How can the template tell which it was given?
I'm thinking the value would be set like one of these:
context = {
'foo' : 'bar
}
or:
context = {
'foo' : ['bar', 'bat', 'baz']
}
Then, the template would have code that looks something like this:
{% if foo isa list %}
{% for item in foo %}
{{ item }}<br>
{% endfor %}
{% else %}
{{ item}}<br>
{% endif %}
I can set it up to have foo or foolist, for example, and check for one or the other. However, it'd be a bit nicer (imo) to just have foo that was either a list or not.
If you intend to do it this way then just add a check that it doesn't have format(in case of string) method and has 0 index, if so then its a list else considered single value
{% if foo.0 and not foo.format %}
{% for item in foo %}
{{ item }}<br>
{% endfor %}
{% else %}
{{ item}}<br>
{% endif %}
I think your approach is needlessly complicated.
I would just go with a list:
views.py
foo_list = ['bar']
context = {
'foo': foo_list,
'foo_len': len(foo_list),
}
template
{% if foo_len == 1 %}
{{ foo.0 }}
{% else %}
{% for item in foo %}
{{ item }}
{% endfor %}
{% endif %}
Related
{% for each_item in item.artifacts %}
{% if each_item.scanner_count > 0 and each_item.scanner_match > 0 %}
{% if forloop.counter <= 5 %}
<tr>
<td>{{each_item.threat_name}}</td>
</tr>
{% else %}
{% if forloop.last %}
<p><b><i> {{ forloop.counter|add:"-5" }} rows were truncated. See full report for more details. </i></b></p>
{% endif %}
{% endif %}
{% else forloop.counter -=1 %}
{% endif %}
{% endfor %}
ERROR:Malformed template tag at line 171: "else forloop.counter -=1"
I want to increment the counter only when if condition is successful. Dont know how to do it with forloop.counter. Goal is to print 5 rows of valid output(scanner count >0 and Scanner match >0)
You can use combination of add and forloop counter to achieve what you want to achieve. But remember you need to pass some variable (I've used rank here for kinda storing the increment variable in template.
views.py
rank = 0
return render(request, "base.html", {"items": items, "rank": rank})
html
{% for each_item in items %}
{% if each_item.scanner_count > 0 and each_item.scanner_match > 0 %}
{% if forloop.counter|add:rank <= 5 %}
<tr><td>{{each_item.threat_name}}</td></tr>
<br>
{% else %}
{% if forloop.last %}
<p><b><i> {{ forloop.counter|add:"-5" }} rows were truncated. See full report for more details. </i></b></p>
{% endif %}
{% endif %}
{% endif %}
{% endfor %}
As other commenters have noted, you cannot make an assignment of the forloop.counter in the template, as that would be considered logic that should be in the view (controller). Remove the {% else forloop.counter -= 1 %} from your code and it should work as I think you intended. If not, either add logic in the object (context) being passed to the template or user other forloop attributes/variables as found in the Django documentation here: https://docs.djangoproject.com/en/3.0/ref/templates/builtins/#for
I try to rebuild this example:
https://blog.roseman.org.uk/2010/01/11/django-patterns-part-2-efficient-reverse-lookups/
I have a model "Product" and a model "Order". Order has a foreignkey to "product". So for 1 Product I have N Orders
In my template I have to display a lot of information so I would like to avoid to do "for order in Product.order_set.all()" in my template
In my template, if I write :
{{ object_list.1.related_items }}
everything is fine and I get what I want
but if I write:
{% for i in object_list %}
{{ object_list.i.related_items }}
{% endfor %}
I don't get a result.
Can somebody tell me how I solve this problem?
My object_list is nearly the same as in the above example:
products = Product.objects.all()
i = 0
qs = Product.objects.all()
obj_dict = dict([(obj.id, obj) for obj in qs])
objects = Order.objects.filter(producttyp__in=qs)
relation_dict = {}
for obj in objects:
relation_dict.setdefault(obj.producttyp_id, []).append(obj)
for id, related_items in relation_dict.items():
obj_dict[id].related_items = related_items
def get(self,request,*args,**kwargs):
context = {'object_list':self.obj_dict}
return render(request,self.template_name,context)
the only change i did is from
obj_dict[id]._related_items to obj_dict[id].related_items because of the not allowed underscore?!
How do I print the list in my template like:
- Product A
- Order 1
- Order 2
- Order 5
- Product B
- Order 3
- Order 6
best regards
That is logical, since here Django interprets i not as the variable, but as the an identifier, so it aims to access object_list.i, or object_list['i'], not object_list.1 for example.
You however do not need i here, you can just access the related_items of the object, like:
{% for object in object_list %}
{{ object.related_items }}
{% endfor %}
If related_items is, as the name suggests, a collection as well, we can iterate over these items as well:
{% for object in object_list %}
{% for subitem in object.related_items %}
{{ subitem }}
{% endfor %}
{% endfor %}
for a dictionary, we can access the .values, like:
{% for object in object_dict.values %}
{{ object.related_items }}
{% endfor %}
EDIT: as for the specific case of the listview. You can use .prefetch_related to fetch all the relations with one extra query:
class MyListView(ListView):
queryset = Product.objects.prefetch_related('order_set')
template = 'my_template.html'
In the template you can then render this like:
<ul>
{% for product in object_list %}
<li>{{ product }}</li>
<ul>
{% for order in product.order_set %}
<li>{{ order }}</li>
{% endfor %}
</ul>
{% endfor %}
</ul>
I'm using the following template code to try to produce a list in the format 'a, b, c and d':
{% for item in list %}
{% if not forloop.first %}
{% if not forloop.last %}
,
{% endif %}
{% endif %}
{% if forloop.last %}
and
{% endif %}
{{ item }}
{% endfor %}
The actual output I'm getting is 'a , b , c and d' (note the spaces before the commas).
What's going on and how do I fix it?
OK, after several attempts I think I've found a solution, it's a bit verbose but it does what you want - no extra spaces -
{% for item in list %}
{% if forloop.revcounter > 2 %}
{{ item }},
{% else %}
{% if forloop.revcounter == 2 %}
{{ item }} and
{% else %}
{{ item }}
{% endif %}
{% endif %}
{% endfor %}
forloop.revcounter is counting down from the end of the loop, so you add the 'and' to the second last item and leave the last one without anything.
Django inserts all the spaces that your template contains:
{% for item in list %}{% if not forloop.first %}{% if not forloop.last %}, {% endif %}{% endif %}{% if forloop.last %} and {% endif %}{{ item }}{% endfor %}
By the way, your template renders the wrong output if the list contains only one value. The corrected template looks like:
{% for item in list %}
{% if not forloop.first %}
{% if forloop.last %}
and
{% else %}
,
{% endif %}
{% endif %}
{{ item }}
{% endfor %}
And without the unwanted space it becomes:
{% for item in list %}{% if not forloop.first %}{% if forloop.last %} and {% else %}, {% endif %}{% endif %}{{ item }}{% endfor %}
I would make a simple template filter:
#register.filter
def format_list(li):
"""
Return the list as a string in human readable format.
>>> format_list([''])
''
>>> format_list(['a'])
'a'
>>> format_list(['a', 'b'])
'a and b'
>>> format_list(['a', 'b', 'c'])
'a, b and c'
>>> format_list(['a', 'b', 'c', 'd'])
'a, b, c and d'
"""
if not li:
return ''
elif len(li) == 1:
return li[0]
return '%s and %s' % (', '.join(li[:-1]), li[-1])
I'm far from an expert in python and there's probably a better way to do it. But still, this seems clean at the "django level", use it as such:
{{ your_list|format_list }}
What I like with this solution is that it is reusable, is more readable, has less code, and has tests.
Check out the documentation on writing template filters for details on how to install it.
Also, you might notice that this function comes with doctests, refer to django documentation to learn how to run the tests.
Here's a way:
>>> python -m doctest form.py -v
Trying:
format_list([''])
Expecting:
''
ok
Trying:
format_list(['a'])
Expecting:
'a'
ok
Trying:
format_list(['a', 'b'])
Expecting:
'a and b'
ok
Trying:
format_list(['a', 'b', 'c'])
Expecting:
'a, b and c'
ok
Trying:
format_list(['a', 'b', 'c', 'd'])
Expecting:
'a, b, c and d'
ok
1 items had no tests:
form
1 items passed all tests:
5 tests in form.format_list
5 tests in 2 items.
5 passed and 0 failed.
Test passed.
I want to change the value of the variable declared outside the loop within a loop. But always changing, it keeps the initial value outside the loop.
{% set foo = False %}
{% for item in items %}
{% set foo = True %}
{% if foo %} Ok(1)! {% endif %}
{% endfor %}
{% if foo %} Ok(2)! {% endif %}
This renders:
Ok(1)!
So the only (bad) solution have found so far was this:
{% set foo = [] %}
{% for item in items %}
{% if foo.append(True) %} {% endif %}
{% if foo %} Ok(1)! {% endif %}
{% endfor %}
{% if foo %} Ok(2)! {% endif %}
This renders:
Ok(1)!
Ok(2)!
But, its is very ugly! Is there another more elegant solution?
Try also dictionary-based approach. It seems to be less ugly.
{% set vars = {'foo': False} %}
{% for item in items %}
{% if vars.update({'foo': True}) %} {% endif %}
{% if vars.foo %} Ok(1)! {% endif %}
{% endfor %}
{% if vars.foo %} Ok(2)! {% endif %}
This also renders:
Ok(1)!
Ok(2)!
as mentioned in the documentation:
Please note that assignments in loops will be cleared at the end of
the iteration and cannot outlive the loop scope.
but as of version 2.10 you can use namespaces:
{% set ns = namespace(foo=false) %}
{% for item in items %}
{% set ns.foo = True %}
{% if ns.foo %} Ok(1)! {% endif %}
{% endfor %}
{% if ns.foo %} Ok(2)! {% endif %}
You could do this to clean up the template code
{% for item in items %}
{{ set_foo_is_true(local_vars) }}
{% if local_vars.foo %} Ok(1)! {% endif %}
{% endfor %}
{% if local_vars.foo %} Ok(2)! {% endif %}
And in the server code use
items = ['item1', 'item2', 'item3']
#---------------------------------------------
local_vars = { 'foo': False }
def set_foo_is_true(local_vars):
local_vars['foo'] = True
return ''
env.globals['set_foo_is_true'] = set_foo_is_true
#---------------------------------------------
return env.get_template('template.html').render(items=items, local_vars=local_vars)
This could be generalized to the following
{{ set_local_var(local_vars, "foo", False) }}
{% for item in items %}
{{ set_local_var(local_vars, "foo", True) }}
{% if local_vars.foo %} Ok(1)! {% endif %}
{% endfor %}
{% if local_vars.foo %} Ok(2)! {% endif %}
And in the server code use
items = ['item1', 'item2', 'item3']
#---------------------------------------------
local_vars = { 'foo': False }
def set_local_var(local_vars, name, value):
local_vars[name] = value
return ''
env.globals['set_local_var'] = set_local_var
#---------------------------------------------
return env.get_template('template.html').render(items=items, local_vars=local_vars)
My dictionary looks like this(Dictionary within a dictionary):
{'0': {
'chosen_unit': <Unit: Kg>,
'cost': Decimal('10.0000'),
'unit__name_abbrev': u'G',
'supplier__supplier': u"Steve's Meat Locker",
'price': Decimal('5.00'),
'supplier__address': u'No\r\naddress here',
'chosen_unit_amount': u'2',
'city__name': u'Joburg, Central',
'supplier__phone_number': u'02299944444',
'supplier__website': None,
'supplier__price_list': u'',
'supplier__email': u'ss.sss#ssssss.com',
'unit__name': u'Gram',
'name': u'Rump Bone',
}}
Now I'm just trying to display the information on my template but I'm struggling. My code for the template looks like:
{% if landing_dict.ingredients %}
<hr>
{% for ingredient in landing_dict.ingredients %}
{{ ingredient }}
{% endfor %}
Print {{ landing_dict.recipe_name }}
{% else %}
Please search for an ingredient below
{% endif %}
It just shows me '0' on my template?
I also tried:
{% for ingredient in landing_dict.ingredients %}
{{ ingredient.cost }}
{% endfor %}
This doesn't even display a result.
I thought perhaps I need to iterate one level deeper so tried this:
{% if landing_dict.ingredients %}
<hr>
{% for ingredient in landing_dict.ingredients %}
{% for field in ingredient %}
{{ field }}
{% endfor %}
{% endfor %}
Print {{ landing_dict.recipe_name }}
{% else %}
Please search for an ingredient below
{% endif %}
But this doesn't display anything.
What am I doing wrong?
Lets say your data is -
data = {'a': [ [1, 2] ], 'b': [ [3, 4] ],'c':[ [5,6]] }
You can use the data.items() method to get the dictionary elements. Note, in django templates we do NOT put (). Also some users mentioned values[0] does not work, if that is the case then try values.items.
<table>
<tr>
<td>a</td>
<td>b</td>
<td>c</td>
</tr>
{% for key, values in data.items %}
<tr>
<td>{{key}}</td>
{% for v in values[0] %}
<td>{{v}}</td>
{% endfor %}
</tr>
{% endfor %}
</table>
Am pretty sure you can extend this logic to your specific dict.
To iterate over dict keys in a sorted order - First we sort in python then iterate & render in django template.
return render_to_response('some_page.html', {'data': sorted(data.items())})
In template file:
{% for key, value in data %}
<tr>
<td> Key: {{ key }} </td>
<td> Value: {{ value }} </td>
</tr>
{% endfor %}
This answer didn't work for me, but I found the answer myself. No one, however, has posted my question. I'm too lazy to
ask it and then answer it, so will just put it here.
This is for the following query:
data = Leaderboard.objects.filter(id=custom_user.id).values(
'value1',
'value2',
'value3')
In template:
{% for dictionary in data %}
{% for key, value in dictionary.items %}
<p>{{ key }} : {{ value }}</p>
{% endfor %}
{% endfor %}
If you pass a variable data (dictionary type) as context to a template, then you code should be:
{% for key, value in data.items %}
<p>{{ key }} : {{ value }}</p>
{% endfor %}
I am thankful for the above answers pointing me in the right direction. From them I made an example for myself to understand it better. I am hoping this example will help you see the double dictionary action more easily and also help when you have more complex data structures.
In the views.py:
bigd = {}
bigd['home'] = {'a': [1, 2] , 'b': [3, 4] ,'c': [5,6] }
bigd['work'] = {'e': [1, 2] , 'd': [3, 4] ,'f': [5,6] }
context['bigd'] = bigd
In the template.html:
{% for bigkey, bigvalue in bigd.items %}
<b>{{ bigkey }}</b> <br>
{% for key, value in bigvalue.items %}
key:{{ key }} <br>
----values: {{ value.0}}, {{value.1 }}<br>
{% endfor %}
<br>
{% endfor %}
Notice the list in the second dictionary is accessed by the index in the list.
Result in browser is something like: