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passing dictionary to view ,with multiple key:value pairs

def status_(request,id):
stages=['Vendor Quotation','Estimate Generation','Purchase Requsition','Purchase Order','Provision To Invoice','Reimbursement Invoice','Request Receipt#(PTI+RI+PO)','Receipt# Received(Updated PTI)','Request Sales Tax Invoice','Uploaded to Jazz Portal']
ctx={'invoice':Invoices.objects.get(pk=id),'stages':stages}
return render(request,"Invoices/status.html",ctx)
Hi I am trying to pass multiple objects of data for displaying to the template for displaying , I am creating a ctx dictionary with multiple 2 key value pairs ,second Key-value pair is array ,when i access this array in by using
{% for idx in range(0,len(ctx.get("stages")) %}
I get following parsing error
**Could not parse the remainder: '(0,len(ctx.get("stages"))' from 'range(0,len(ctx.get("stages"))'**

You can not make function calls in Django templates with parameters, hence the above wiull not work, but likely you do not need this anyway, you can simply enumerate with:
{% for stage in stages %}
{{ stage }}
{% endfor %}
If you really need to enumerate, then you can pass a range object through the context, but then probably a next problem pops up: you can not subscript with a variable either. It will require using a lot of extra template filters, making it very complicated. Templates are normally not used to implement business logic, therefore Django has a template engine that does not support complicated function calls, etc. to give the developer an incentive to move the business logic to the view.

Can I use a variable as index in for loop in python?

I have this for loop on my python template to fulfill an array of values:
labels: [{% for bftimes in dataBF.buffers.0.times %} "{{ bftimes }}", {% endfor %}]
I would like to know if I can use an int variable as an index instead writing it directly, as seen on the code above.
I need to use the index of the selected value of a dropdown:
//returns the index of the selected value
document.getElementById("buffer").selectedIndex

The question needs more context to help us understand your goal. It seems you are mixing python with javascript data structures.
My general recommendation is that you first prepare the python data structure to what you will need and then convert it to json. Looping within Django template language should be used only on simple cases.
If you use django>=2.1 you can use json-script template tag
{{ data|json_script:"my-data" }}
https://docs.djangoproject.com/en/2.1/ref/templates/builtins/#json-script
If not, you can use
# views.py
import json
def foo(request):
dataBF = {"a": [{"c": [1,2,3,1,1]},{"d": [1,2,3,1,1]}]}
# here you can manipulate the data accordingly to what you need
data = json.dumps(dataBF)
return render(request, "index.html", context={"data": data})
On the template side
<script>
const datajs = {{ data | safe }};
</script>
The datajs is a javascript object that you can work with.
I've made an example that you can check https://repl.it/#IvanPereira/python-to-javascript-django-template

You can do this in 2 ways.
Store all values in a list, which JavaScript will consider as json array, and loop over using JavaScript itself. This way you won't be able to update records from server and all values that has to be looped over should be pre-fetched.
You can use AJAX call to pass the selected index from JavaScript and return the new array and update that in the template using JavaScript itself.

Is it possible to accumulate values with increment in a Django template?

I would like to know if there is any way to sum values in a variable in a Django template using {% for obj in objects %}. Something like this:
for student in students:
notes += student.note
Using the mathfilters or something similar to make the sum
Thanks!

If you want sum values in template you can use with tag
please read this link for more information
https://docs.djangoproject.com/en/1.10/ref/templates/builtins/#with

You can use add filter.
It is a not a good idea to do so anyway. You want to keep your logic inside the views and keep the rendering inside the templates.
You can also use django-mathfilters
{% load mathfilters %}
{{ num1 | addition:num2 }}

How can I limit the number of queries when retrieving all related objects from multiple models?

Lets say I have this model:
class MyLogModel(models.Model):
log_stuff = models.CharField(max_length)
class MoreLogModel(models.Model):
word = models.CharField(max_length)
my_log_model = models.ForeignKey(MyLogModel, related_name="more_log_models")
Now imagine there are 1.000.000.000 MyLogModel and ten times more MoreLogModel which relate to them.
In my view I want to show the user the latest 100 MyLogModel and all the 'word' fields of the MoreLogModel that are relating to them. On average there should be 10 MoreLogModel per MyLogModel.
But if I just use (pseudo code):
my_log_model_query = MyLogModel.objects.get_latest_100
And then loop through it in the template always putting another loop:
{% for my_log in my_log_model_query %}
{% for more_log_model my_log.more_log_models %}
{{ more_log_model.word }}
{% endfor %}
{% endfor %}
That will cause an insane amount of database queries right?
So what I'm wondering is if it is possible to query all MyLogModel with the related "more_log_models" already in a list attached to that model?
The reason why I have the foreign key relationship is because the data comes from a server process that is multi threaded and puts in the "word" whenever it feels like it.
So any ideas how I can solve this problem in general?
Also:
Another way I used before was to have only one model wich has a word field and a group_id. This word field then only contains one word and there is one entry for every word. That causes the 'log_stuff' to be duplicated, but I don't see a big problem with that. What was a huge problem is to go though all these logs and combine them according to the group ids and then sort them based on time again. In the end this causes less queries, but I have to sort everything at least twice which is not very fast.

Why can't iterate through this list in a Django template

I have a variable from my view that is the output of a Model.objects.all() call on that Model. I'm passing it to my template in my view, and I'm trying to iterate over it in the template. I can access the first element of it simply by this line of code. 'code' is the name of a field in my django model. This line does print the first element's 'code' attribute correctly.
{{ var_name.0.code }}
However, when I try to iterate over var_name in a template for loop, nothing shows up. I tried the following code:
{% for single_var in var_name %}
{{ single_var.code }}
{% endfor %}
This isn't actually what I want to do in the for loop, but getting this to work will let me do what I need in the template. It may be noteworthy to add that at the moment this list has only one element in it.
This is for a work project, so that's why I changed the variable names to something generic.

I found that changing the name of single_var to something without an underscore seemed to fix it. This doesn't make a lot of sense to me because the Django template language documentation states the following:
Variable names consist of any combination of alphanumeric characters and the underscore ("_").
Does anyone know why this seemed to fix the problem?