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checking which decimal is bigger django

Im having problem with one line of code... Im trying to check which decimal is greater, i checked few answers from stackoverflow and they didnt work (probably cuz they were from 7 years ago :P) anyways here is my view:
auction = all_auctions.objects.get(id= my_id)
comment_num = auction.comments.all().count()
all_comments = auction.comments.all()
context = {
"auction": auction,
"bid_auction": auction.bid.all(),
"comment_num": comment_num,
"all_comments": all_comments
}
if request.method == "POST" and "bid" in request.POST:
if request.user.is_authenticated:
highest_bid = request.POST["bid"]
if not Decimal(highest_bid) <= Decimal(int(auction.bid.all().reverse()[0])):
all_bid = bids.objects.create(bid = highest_bid)
auction.bid.add(all_bid)
if request.method == "POST" and "watch"in request.POST:
if request.user.is_authenticated:
if auction not in request.user.watchlist.all():
request.user.watchlist.add(auction)
else:
request.user.watchlist.remove(auction)
if request.method == "POST" and "comment" in request.POST:
comment = request.POST["comment"]
if request.user.is_authenticated:
comment_now = comments.objects.create(comment = comment)
auction.comments.add(comment_now)
return render(request, "auctions/dynamic_auction.html", context)
and there is the problematic line:
if not Decimal(highest_bid) <= Decimal(int(auction.bid.all().reverse()[0])):
in models:
from django.contrib.auth.models import AbstractUser
from django.db import models
class comments(models.Model):
comment = models.TextField(blank=False)
class bids(models.Model):
bid = models.DecimalField(decimal_places = 2, max_digits = 100000)
class all_auctions(models.Model):
category = models.CharField(max_length= 14, default = "none")
title = models.CharField(max_length= 14)
description = models.TextField(blank=False)
photo_url = models.CharField(max_length= 500000)
bid = models.ManyToManyField(bids, blank = True, related_name = "bid_auction")
comments = models.ManyToManyField(comments, blank = True, related_name = "comments")
class User(AbstractUser):
created = models.ManyToManyField(all_auctions, blank = True, related_name = "created")
watchlist = models.ManyToManyField(all_auctions, blank = True, related_name = "watchlist")
user_bid = models.ManyToManyField(bids, blank = True, related_name = "user_bid")
and in the template where i can place bids and view them:
{% extends "auctions/layout.html" %}
{% block body %}
<div>
<h2>{{auction.title}}</h2>
<div style = "width: 1400px; padding: 10px; margin: 10px;" class = auction_class>
<img src="{{auction.photo_url}}" alt="no image">
<div>
{{auction.description}}
<p></p>
{% for bid in bid_auction %}
{% if forloop.last %}
bid:{{bid.bid}}
{% endif %}
{% endfor %}
<p></p>
{{auction.category}}
<p></p>
{% if user.is_authenticated %}
<form method = "POST"> {% csrf_token %}
<input class="btn btn-primary" type="submit" name = "watch" value="Add to watchlist">
</form>
<form method = "POST"> {% csrf_token %}
<div>
<input style = "margin:10px;" class="form-control" name = "bid" type="text" placeholder= "Bid...">
<input class="btn btn-primary" type="submit" value="Place Bid">
</div>
</form>
<form method = "POST"> {% csrf_token %}
<div>
<input style = "margin:10px;" class="form-control" name = "comment" type="text" placeholder= "Comment...">
</div>
</form>
{% endif %}
<p></p>
comments:
<p></p>
{% if comment_num == 0 %}
no comments
{% endif %}
<p></p>
<p></p>
{% for com in all_comments %}
{{ com.comment }}
<p></p>
{% endfor %}
</div>
</div>
</div>
{% endblock %}
and yes i made it so the last object of the bids queryset is shown, i have no idea how to show the biggest one, so also i would appreciate help with that . thanks :D

I guess this:
if not Decimal(highest_bid) <= Decimal(int(auction.bid.all().reverse()[0].bid)):
should work (note .bid in the end).
And why you can't use [-1]?

Although I haven't worked with django alot but since you want to compare decimals you could technically create a class which inherits the class Decimal() and then return a float and compare that float. Although I think this won't work (I haven't tried it because I don't like django in particular) but this could be a possibility.
EDIT:
Use a function to return a float from the class.
Example Code:
class DecimalNumber(Decimal):
def __init__(self, value, par2...):
self.value = value
...
def return_float(self):
float = self.value
return float

Django Order QuerySet by Min Value from Child Table

I am trying to create a specific complex query in Django that I am struggling with.
I am using pagination to display a list of cakes on the index page. I want to sort them by different attributes. Below is a screenshot of my index page.
Name (A-Z) & Name (Z-A) are implemented by simply ordering the Cake queryset by 'name' or '-name' which I am getting as POST from the form at the top of the page.
cakes_list = Cake.objects.all().order_by('name')
However I am struggling to order the queryset by minimum price.
Each cake is available in different dimensions which have different prices (dimensions and prices between cakes are different). These are stored in Dimension with a foreign key pointing to the Cake they belong to.
I want to find out the cheapest option for each cake and order my list of cakes that is used in the pagination based on that (both min price asc and desc).
I have also created a method from_price which returns the price of that cake. Which I use in my template to display each cake name together with the minimum price. But I cannot seem to be able to implement that into my sorting.
I appreciate help with how I can create a query or similar that allows me to sort all of my cakes based on the minimum price for each. I am just learning Django, so my current implementations might not be ideal.
vault/models.py:
class Cake(models.Model):
name = models.CharField(max_length=200)
def from_price(self):
temp = self.dimension_set.aggregate(Min('price')).get('price__min')
if not temp:
temp = 0
return temp
class Dimension(models.Model):
cake = models.ForeignKey(Cake, on_delete=models.CASCADE)
dimension = models.CharField(max_length=50)
price = models.DecimalField(max_digits=6, decimal_places=2)
vault/views.py
def index(request):
#from the form on the index page
order_by = request.POST.get('order_by')
if not order_by:
order_by = 'name'
cakes_list = Cake.objects.all().order_by(order_by)
paginator = Paginator(cakes_list, 5)
page_number = request.GET.get('page', 1)
page_obj = paginator.get_page(page_number)
return render(request, 'vault/index.html', {'page_obj': page_obj, 'order_by': order_by})
vault/templates/vault/index.html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
{# Form for cake sorting dropdown #}
<form action="{% url 'vault:index' %}" method="post">
{% csrf_token %}
<label for="order_by">Order by:</label>
<select name="order_by" id="order_by">
<option {% if order_by == "name" %} selected="selected" {% endif %} value="name">Name (A-Z)</option>
<option {% if order_by == "-name" %} selected="selected" {% endif %} value="-name">Name (Z-A)</option>
{% comment %}
New options for ordering by price
<option {% if order_by == "" %} selected="selected" {% endif %} value="name">Price from (Low to High)</option>
<option {% if order_by == "" %} selected="selected" {% endif %} value="-name">Price from (High to Low)</option>
{% endcomment %}
</select>
<input type="submit" value="Select">
</form>
{# Code for printing the list of cakes #}
{% if page_obj %}
<ul>
{% for cake in page_obj %}
<li>
<a href="{% url 'vault:detail' cake.id %}">
{{ cake.name }}
{% if cake.from_price %}
- from £{{ cake.from_price|floatformat:'2' }}
{% endif %}
</a>
</li>
{% endfor %}
</ul>
{% else %}
<p>No cakes are available</p>
{% endif %}
{# Code for the pagination navigation elements #}
<div class="pagination">
<span class="step-links">
{% if page_obj.has_previous %}
« first
previous
{% endif %}
<span class="current">
Page {{ page_obj.number }} of {{ page_obj.paginator.num_pages }}.
</span>
{% if page_obj.has_next %}
next
last »
{% endif %}
</span>
</div>
</body>
</html>

Try to use annotation before ordering like that:
cakes_list = Cake.objects.annotate(
max_price=Max('dimension__price'),
).order_by('max_price')

If you need a min price value on each Cake record then probably the easies way is to use subquery:
from django.db.models import OuterRef, Subquery
sub_q = Dimension.objects.filter(cake=OuterRef('id')).order_by('price')
qs = Cake.objects.annotate(min_price=Subquery(sub_q.values('prize')[:1]).order_by('min_price')

How do i access the properties of a many-to-many with Membership in Django

How can i set only mine membership, instead of all in for-loop ?
template.html:
{% for g in gr %}
<div class="jumbotron">
<div class="jumbo2">
<form method="POST" class="post-form"> {% csrf_token %}
<p id="name"><b>Groups name:</b> {{g.name}}</p><br>
{% for membership in g.membership_set.all %}
<p><b>Member:</b> {{ membership.person }} - {{ membership.role }}</p>
{% endfor %}
<br>
<span class="desc2">Groups description:</span>
<p id="desc">{{g.description}}</p><br>
{% for membership in g.membership_set.all %}
{% if membership.leader == False %}
<button style="float: right" type="submit" name = "leave" value = "{{g.name}}" class="save btn btn-default">Leave</button>
{% elif membership.leader == True %}
<button style="float: right" type="submit" name = "delete" value = "{{g.name}}" class="save btn btn-default">Delete</button>
{% endif %}
{% endfor %}
</form>
<br><br>
<p></p>
</div>
</div>
{% endfor %}
models.py:
class Person(models.Model):
name = models.CharField(max_length=128)
def __str__(self): # __unicode__ on Python 2
return self.name
class Group(models.Model):
name = models.CharField(max_length=128)
members = models.ManyToManyField(Person, through='Membership')
description = models.TextField(max_length=350)
def __str__(self): # __unicode__ on Python 2
return self.name
class Membership(models.Model):
person = models.ForeignKey(Person)
leader = models.BooleanField(default=False)
group = models.ForeignKey(Group)
role = models.CharField(max_length=50)
My buttons are displeyed as many as i have users in some group.
I want to display only 1 button, and i need to precise ForLoop only for my membership in this group. How can i do this?

I don't think you can do this just by using standard template code. You would need to get your Membership object by filtering the memberships like so:
membership = my_person.membership_set.get(group=my_group)
To do this in the template, you would have to write your own template filter that works on the my_person object and takes the my_group object as parameter. The filter could then apply the above query and return the membership object.
{% with membership=my_person|get_group_membership:g %}
{% if membership.leader == False %}
<button style="float: right" type="submit" name = "leave" value = "{{g.name}}" class="save btn btn-default">Leave</button>
{% elif membership.leader == True %}
<button style="float: right" type="submit" name = "delete" value = "{{g.name}}" class="save btn btn-default">Delete</button>
{% endif %}
{% endwith %}

Django Template - neat 1-1 translation of values (dictionary lookup)

I've an object containing an attribute defined by a series of choices - here's it's class definition:
class StashURLJobRequest(models.Model):
STATUS_CHOICES = ((0,"Requested"),(1,"Done"),(2,"Failed"))
url = models.URLField()
created = models.DateTimeField(auto_now_add = True, auto_now=False)
processed = models.DateTimeField(auto_now_add = False, auto_now = True)
status = models.IntegerField(choices=(STATUS_CHOICES))
requestBy = models.CharField(max_length=32)
def __unicode__(self):
return smart_unicode(self.url + str(self.created))
def status_display(self):
status_dict = dict(self.STATUS_CHOICES)
return status_dict[self.status]
I get a list of these and pass through into a template, intending to render each one as an individual row, again, here's the template code:
{% for job_instance in jobs %}
<div class="width100pc">
<div class="width10pc"> <img src="{% static 'img/empty.png' %}" /> </div>
<div class="width80pc">
<div class="width70pc textleft sans textsmall "> {{ job_instance.url }} </div>
<div class="width15pc textcentre sans texttiny "> {{ job_instance.processed }} </div>
<div class="width5pc textcentre sans texttiny {% ifequal job_instance.status_display 'Done' %} status_green {% endifequal %}
{% ifequal job_instance.status_display 'Requested' %} status_amber {% endifequal %}
{% ifequal job_instance.status_display 'Failed' %} status_red {% endifequal %}"> {{ job_instance.status_display }} </div>
<div class="width10pc textcentre sans texttiny"> {{ job_instance.requestBy }} </div>
</div>
<div class="width10pc"> <img src="{% static 'img/empty.png' %}" /> </div>
</div>
{% endfor %}
In particular, note the section:
{% ifequal job_instance.status_display 'Done' %} status_green {% endifequal %}
{% ifequal job_instance.status_display 'Requested' %} status_amber {% endifequal %}
{% ifequal job_instance.status_display 'Failed' %} status_red {% endifequal %}
Each of {status_green, status_amber and status_red} refer to a different css class, and allows me to render the status in an appropriate colour.
This seems a little unwieldy, and I don't want to code the css-class into the model, or the view (preferring to leave format and display to the template/html definitions) - so the question is, is there a way to do this that's more "pythonic" - ideally, I'd like to use something like:
{{ class_dict = {'Done' : 'status_green', 'Requested' : 'status_amber', 'Failed' : 'status_red' } }}
< ... some code ... >
{{ class_dict[job_instance.status_display] }}
(dodgy curly-braces aside!)

Add a helper function to the object, so that you don't need any logic in the template?
Add to StashURLJobRequest
def status_display_colour(self):
return {
"Done":"status_green",
"Requested":"status_amber",
"Failed":"status_red"
}[ self.status_display() ]
And the template becomes <div class="width5pc textcentre sans texttiny {{ job_instance.status_display_colour }} ...
Another way would be class="... my-class-{{job_instance.status_display}}" with my-class-Done, my-class-Requested, my-class-Failed appropriately defined in your css. It's inferior because it depends implicitly on status_display remaining a single word with no spaces or other special characters.

Next and Before Links for a django paginated query

I'm trying to make a search form for Django.
Its a typical search form and then returns a table of matches. I wish to paginate the tables returned.
The problem lies in the Previous and Next buttons.
The links for the return query goes to /records/search/?query=a (search sample is a)
The page outputs the table and its previous and next links. However the links redirect to /records/search/?page=2 and the page displays a blank table.
Any help on which links I should pass for Prev/Next?
search.html:
{% extends 'blank.html' %}
{% block content %}
<div class="row">
<form id="search-form" method="get" action=".">
{{ form.as_p }}
<input type="submit" value="Search" />
</form>
</div>
<br><br>
//display table code//
{% if is_paginated %}
<div class="pagination">
<span class="step-links">
{% if agent_list.has_previous %}
forrige
{% endif %}
<span class="current">
Page {{ agent_list.number }} of {{ agent_list.paginator.num_pages }}.
</span>
{% if agent_list.has_next %}
Next
{% endif %}
</span>
</div>
{% endif %}
{% endblock %}
and the search view:
def search_page(request):
form = SearchForm()
agents = []
show_results=False
if request.GET.has_key('query'):
show_results=True
query=request.GET['query'].strip()
if query:
form=SearchForm({'query': query})
agents = \
Agent.objects.filter(Q(name__icontains=query))
paginator = Paginator(agents, 10)
page = request.GET.get('page')
try:
agents = paginator.page(page)
except PageNotAnInteger:
agents = paginator.page(1)
except EmptyPage:
agents = paginator.page(paginator.num_pages)
variables = RequestContext(request,
{ 'form': form,
'agent_list': agents,
'show_results': show_results,
'is_paginated': True,
}
)
return render_to_response('search.html', variables)
I've seen the similar questions but I can't understand/make them work. Any help?
Edit:
For a quickfix (haven't really looked at the cons)
I added a variable in my view:
variables = RequestContext(request,
{ 'form': form,
'agent_list': agents,
'show_results': show_results,
'is_paginated': True,
**'query': query,**
}
)
Where query without the quotes is the recieved query variable.
Then simply change the URL to:
Previous
If you have a better way of answering the question, please do or appending a URL to your currently opened URL.

I would recommend putting the solution in a template tag like so:
myapp/templatetags/mytemplatetags.py:
from django import template
register = template.Library()
#register.simple_tag
def url_replace(request, field, value):
d = request.GET.copy()
d[field] = value
return d.urlencode()
#register.simple_tag
def url_delete(request, field):
d = request.GET.copy()
del d[field]
return d.urlencode()
Then from templates do:
{% load mytemplatetags %}
...
previous

you can use {{ request.get_full_path }} this tag to get current url.
Next
this worked for me

The below works before and after a search form has been submitted:
Views.py
class PostListView(ListView):
model = Post #.objects.select_related().all()
template_name = 'erf24/home.html' # <app>/<model>_<viewtype>.html
context_object_name = 'posts' # default >> erf24/post_list.html
ordering = ['date_posted']
paginate_by = 3
def is_valid_queryparam(param):
return param != '' and param is not None
def invalid_queryparam(param):
return param == '' and param is None
class SearchView(ListView):
model = Post #.objects.select_related().all()
template_name = 'erf24/home.html' # <app>/<model>_<viewtype>.html
context_object_name = 'posts' # default >> erf24/post_list.html
ordering = ['date_posted']
paginate_by = 3
def get_queryset(self): # new
key = self.request.GET.get('key')
minp = self.request.GET.get('min')
maxp = self.request.GET.get('max')
if is_valid_queryparam(key):
obj = Post.objects.filter(Q(content__icontains=key) | Q(location__icontains=key)).distinct().order_by('date_posted')
if is_valid_queryparam(minp):
obj = Post.objects.filter(Q(price__gte=minp)).distinct().order_by('date_posted')
if is_valid_queryparam(maxp):
obj = Post.objects.filter(Q(price__lte=maxp)).distinct().order_by('date_posted')
if is_valid_queryparam(minp) & is_valid_queryparam(maxp):
obj = Post.objects.filter(Q(price__gte=minp) & Q(price__lte=maxp)).distinct().order_by('date_posted')
if is_valid_queryparam(key) & is_valid_queryparam(minp) & is_valid_queryparam(maxp):
obj = Post.objects.filter(Q(content__icontains=key) | Q(location__icontains=key)).distinct()
obj = obj.filter(Q(price__gte=minp) & Q(price__lte=maxp)).order_by('date_posted')
if invalid_queryparam(key) & invalid_queryparam(minp) & invalid_queryparam(maxp):
obj = Post.objects.all()
return obj
url.py
urlpatterns = [
path('', PostListView.as_view(), name='erf24-home'),
path('search/', SearchView.as_view(), name='erf24-search'),
]
Home.html
<form action="{% url 'erf24-search' %}" method="GET">
<div class="form-group">
<label for="inputAddress">Search keyword</label>
<input type="text" class="form-control" id="key" name="key" placeholder="keyword">
</div>
<label for="">Price</label>
<div class="form-row">
<div class="form-group col-md-6">
<input type="number" class="form-control" id="min" name="min" placeholder="min price">
</div>
<div class="form-group col-md-6">
<input type="number" class="form-control" id="max" name="max" placeholder="max price">
</div>
</div>
<button type="submit" class="btn btn-primary btn-sm mt-1 mb-1">Search</button>
<button type="reset" class="btn btn-secondary btn-sm mt-1 mb-1">Clear</button>
</form>
{% for post in posts %}
<article class="media content-section">
<div class="media-body">
<div class="article-metadata">
<img class="rounded-circle article-img" src="{{ post.author.profile.image.url }}" alt="">
{{ post.author }}
<small class="text-muted">{{ post.date_posted }}</small>
<!-- use |date: "specs" to filter date display -->
</div>
<h2>
{{ post.price }}
</h2>
<p class="article-content">{{ post.content }}</p>
<p class="article-content">{{ post.location }}</p>
<p><a class="like-btn" data-href="{{ post.get_api_like_url }}" href="">{{ post.likes.count }}
{% if user in post.likes.all %} Unlike
{% else %} Like
{% endif %}
</a></p>
</div>
{% for image in post.image_set.all %}
<img class="account-img" src="{{ image.image.url }}" alt="">
{% endfor %}
</article>
{% endfor %}
{% if is_paginated %}
{% if page_obj.has_previous %}
First
Previous
{% endif %}
{% for num in page_obj.paginator.page_range %}
{% if page_obj.number == num %}
{{ num }}
{% elif num > page_obj.number|add:'-3' and num < page_obj.number|add:'3' %}
{{ num }}
{% endif %}
{% endfor %}
{% if page_obj.has_next %}
Next
Last
{% endif %}
{% endif %}
Worked like a charm :) Enjoy!

You can use {{ request.get_full_path }} template tag
Next

you can use this, I use it because I use filters in the url itself, so all the url params are used to build the next or previous url
import re
from django import template
register = template.Library()
PAGE_NUMBER_REGEX = re.compile(r'(page=[0-9]*[\&]*)')
#register.simple_tag
def append_page_param(value,pageNumber=None):
'''
remove the param "page" using regex and add the one in the pageNumber if there is one
'''
value = re.sub(PAGE_NUMBER_REGEX,'',value)
if pageNumber:
if not '?' in value:
value += f'?page={pageNumber}'
elif value[-1] != '&':
value += f'&page={pageNumber}'
else:
value += f'page={pageNumber}'
return value
then, in your pagination nav you can call it like this:
{% append_page_param request.get_full_path page_obj.previous_page_number %}