Django get a queryset and filter by own queryset item

Question

first of all, I cant find the way to explain what I'm intend to do properly so I'll try to do it the best way I can, hope it make sense to you.

I'm trying to display on my index page a list of items that meet a certain criteria. I am creating an inventory app and I want to get a list of all items that need to be resupplied.

views.py

def index(request):
    template_name = 'inventario/index.html'
    model = Item

    # GETS ALL ALCTIVE ITEMS
    articulos = Item.objects.all().filter(activo=True)

    for i in articulos:
        # PRINTS THE VALUE OF 'cantidad_existente' AND 'cantidad_minima' ON EACH ITERATION 
        print(F'--->>>>>>{i.cantidad_existente}<<<<<<<---CANTIDAD EXISTENTE')
        print(F'--->>>>>>{i.cantidad_minima}<<<<<<<---CANTIDAD MINIMA')

        # TRIES TO GET FILTERD VALUE  FOR EACH ITEM 
        articulo =  Item.objects.filter(cantidad_existente__lte=i.cantidad_minima)


        print(F'--->>>>>>{articulo}<<<<<<<---')

    # print(F'--->>>>>>{articulo}<<<<<<<---')

    return render(request, template_name)#, {'items': items})

results in terminal

--->>>>>>6<<<<<<<---CANTIDAD EXISTENTE
--->>>>>>20<<<<<<<---CANTIDAD MINIMA
--->>>>>><QuerySet [<Item: Rondana 1/8>, <Item: Cortador Carburo 1/8>]><<<<<<<---
--->>>>>>2<<<<<<<---CANTIDAD EXISTENTE
--->>>>>>5<<<<<<<---CANTIDAD MINIMA
--->>>>>><QuerySet [<Item: Cortador Carburo 1/8>]><<<<<<<---

So I can see that every iteration brings back cantidad_minima and cantidad_existente for each item in the queryset. My reasoning is that every iteration it would query my database bring back my result i wanted but its not. what am i doing wrong and how can i go about this issue

UPDATE:

I have made some changes to my query and now its working the way I wanted to (sorts of).

updated function on views.py

def index(request):
    template_name = 'inventario/index.html'
    model = Item

    # GETS ALL ALCTIVE ITEMS
    articulos = Item.objects.all().filter(activo=True)
    l = []
    for i in articulos:
        # PRINTS THE VALUE OF 'cantidad_existente' AND 'cantidad_minima' ON EACH ITERATION 
        print(F'--->>>>>>{i.cantidad_existente}<<<<<<<---CANTIDAD EXISTENTE')
        print(F'--->>>>>>{i.cantidad_minima}<<<<<<<---CANTIDAD MINIMA')

        # TRIES TO GET FILTERD VALUE  FOR EACH ITEM 
        articulo =  Item.objects.filter(cantidad_existente__lte=i.cantidad_minima).filter(pk=i.pk)
        if articulo:
            l.append(articulo)

        print(F'--->>>>>>{articulo}<<<<<<<---')

    print(F'--->>>>>>{l}<<<<<<<---')

    return render(request, template_name, {'items': l})

now the problem I have is how to display the elements on my template, how can I iterate over a list to get an item in a queryset?

results in terminal

--->>>>>>21<<<<<<<---CANTIDAD EXISTENTE
--->>>>>>20<<<<<<<---CANTIDAD MINIMA
--->>>>>><QuerySet []><<<<<<<---
--->>>>>>4<<<<<<<---CANTIDAD EXISTENTE
--->>>>>>5<<<<<<<---CANTIDAD MINIMA
--->>>>>><QuerySet [<Item: Cortador Carburo 1/8>]><<<<<<<---

UPDAtE 2: Adding models

I'm using Item that has all common field to all tools in my inventory and this class gets inherited by other classes that have field unique to a specific tool.

class Item(models.Model):
    description = models.CharField(max_length=100,)
    numero_parte = models.CharField(max_length=100)
    proveedor = models.ForeignKey(Proveedor, on_delete=models.CASCADE)
    cantidad_existente = models.PositiveIntegerField()
    update = models.PositiveIntegerField(blank=True, default=0)
    cantidad_minima = models.PositiveIntegerField()
    precio_unitario = models.DecimalField(max_digits=7, decimal_places=2)
    total = models.DecimalField(max_digits=7, decimal_places=2, blank=True)
    # asignado_a = models.ForeignKey(Empleados, on_delete=models.CASCADE, blank=True, null=True)
    anaquel = models.CharField(max_length=2, choices=ANAQUEL, blank=True, null=True)
    posicion_en_x = models.CharField(max_length=2, blank=True, null=True)
    posicion_en_y = models.CharField(max_length=2, blank=True, null=True)
    activo = models.BooleanField()

    def save(self,*args,**kwargs):
        self.total = self.cantidad_existente * self.precio_unitario
        super().save(*args,**kwargs)

    def __str__(self):
        return self.description 


class Cortadores(Item):
    tipo = models.ForeignKey(Tipos_Cortadores,on_delete=models.CASCADE)
    material = models.ForeignKey(Materiales, on_delete=models.CASCADE)
    filos = models.CharField(max_length=10, choices=GABILANES)
    diametro = models.ForeignKey(Diametros, on_delete=models.CASCADE)
    longitud = models.ForeignKey(Longitud, on_delete=models.CASCADE)
    desbaste = models.CharField(max_length=1, choices=DESBASTE)

    class Meta:
        verbose_name_plural = "Cortadores"

    def get_absolute_url(self):
        return reverse('inventario:cortadores-list', kwargs={'id': self.tipo.id})

    def __str__(self):
        return '%s %s %s %s %s %s' % (  str(self.tipo), str(self.material), str(self.filos), str(self.diametro), 
                                        self.longitud, self.desbaste
                                        )

index.html

{% block lista %}
    <div class="container cf">
        <div class="lista">
            {% if items %}
            <table id="tablas" class="cf">
                <tr class="theader">
                    <th>Tipo</th>
                    <th>Descripcion </th>
                    <th>No. Parte</th>
                    <th>Proveedor</th>
                    <th>C. Existente</th>
                    <th>C. Minima </th>
                    <th>Locaci&oacute;n</th>

                </tr>

                {% for c  in items %}
                    <tr class="list-index" >
                        <td>{{c.cortadores.tipo.c}}</td>
                        <td>{{c.description}}</td>
                        <td>{{c.numero_parte}}</td>
                        <td>{{c.proveedor}}</td>
                        <td>{{c.cantidad_existente}}</td>
                        <td>{{c.cantidad_minima}}</td>
                        <td>Anaquel: {{c.anaquel}} | {{c.posicion_en_x}} | {{c.posicion_en_y}}</td>
                    </tr>

                {% endfor%}
            </table>

            {% else %}

                <h1>No hay articulos por vencer</h1>
            {%endif%}

        </div>
    </div>

{% endblock lista%}

Answer 1

try this

GETS ALL ALCTIVE ITEMS

articulos = Item.objects.all().filter(activo=True,)
l = []
for i in articulos:


    # TRIES TO GET FILTERD VALUE  FOR EACH ITEM 
    articulo =  Item.objects.filter(pk=i.pk,cantidad_existente__lte=i.cantidad_minima)
    if articulo:
        l.append(articulo[0])


return render(request, template_name, {'items': l})

Answer 2

Since you are sending your list as context, so you can just iterate over the list in your template

{% for item in items %}
    <tr>
        <td>{{ item.0 }}</td>
        <td>{{ item.1 }}</td>
        ...
    </tr>
{% endfor %}

If that doesn't work try adding the field names after the index like {{ item.0.description }}