Remove as much list comprehension as possible.

Using aggregate functions instead.

beer/models.py

@@ -1,4 +1,5 @@
 from django.db import models
+from django.db.models import Sum, Q
 from django.utils import timezone
 from django_cryptography.fields import encrypt
 from django.core.validators import MinValueValidator
@@ -113,20 +114,21 @@ class Recipe(CustomModel):
         verbose_name = 'Recipe'
         verbose_name_plural = 'Recipes'
 
-    @property
-    def fermentables(self):
-        return [x for x in list(self.recipefermentable_set.all())]
-
     @property
     def fermentable_weight(self):
-        return sum([x.quantity for x in self.fermentables])
+        """Weight of all fermentables attached to recipe."""
+        aggregate = self.recipefermentable_set.all().aggregate(Sum('quantity'))
+        return aggregate['quantity__sum']
 
     @property
-    def hops(self):
+    def hop_weight(self):
-        return [x for x in list(self.recipehop_set.all())]
+        """Weight of all fermentables attached to recipe."""
+        aggregate = self.recipehop_set.all().aggregate(Sum('quantity'))
+        return aggregate['quantity__sum']
 
     @property
     def final_volume(self):
+        """Return final volume (after boil)."""
         return (float(self.batch_size)
                 + self.hop_water_loss
                 + self.net_kettle_deadspace
@@ -134,44 +136,51 @@ class Recipe(CustomModel):
 
     @property
     def sugar_yield(self):
+        """Return point yield of all non-mashed ingredients."""
         ferm_yield = 0
 
-        sugars = (x for x in self.fermentables
+        ferms = self.recipefermentable_set.all().select_related('fermentable')
-                  if x.fermentable.fermentable_type == 3)  # Is sugar
+        sugars = ferms.filter(fermentable__fermentable_type=3)
 
         for f in sugars:
-            ferm_yield += f.quantity * (f.fermentable.potential - 1) * 1000
+            ferm_yield += f.ferm_yield
 
         return float(ferm_yield)
 
     @property
     def mash_yield(self):
+        """Return point yield of all mashed ingredients."""
         mash_yield = 0
 
-        mashed = (x for x in self.fermentables
+        ferms = self.recipefermentable_set.all().select_related('fermentable')
-                  if x.fermentable.fermentable_type != 3)  # Is not sugar
+        # Is not sugar (3)
+        mashed = ferms.filter(~Q(fermentable__fermentable_type=3))
 
         for f in mashed:
-            mash_yield += (f.quantity * (self.efficiency / 100)
+            mash_yield += f.ferm_yield
-                           * (f.fermentable.potential - 1) * 1000)
 
         return float(mash_yield)
 
     @property
     def original_sg(self):
+        """Return original gravity."""
         total_yield = self.sugar_yield + self.mash_yield
-        return round(1 + total_yield / self.final_volume / 1000, 3)
+        gravity_points = total_yield/self.final_volume
+        return round(1 + gravity_points/1000, 3)
 
     @property
     def pre_boil_sg(self):
+        """Return pre-boil gravity."""
         total_yield = self.sugar_yield + self.mash_yield
-        return round(1 + total_yield / (self.final_volume
+        total_water = self.final_volume+self.boil_off_gph
-                     + self.boil_off_gph) / 1000, 3)
+        gravity_points = total_yield/total_water
+        return round(1 + gravity_points/1000, 3)
 
     @property
     def hop_water_loss(self):
-        hop_absorption = .025  # gallons per ounce
+        return float(sum(
-        return sum([float(x.quantity) * hop_absorption for x in self.hops])
+            x.quantity*x.trub_volume for x in self.recipehop_set.all()
+        ))
 
     @property
     def net_kettle_deadspace(self):
@@ -206,11 +215,12 @@ class Recipe(CustomModel):
 
     @property
     def ibu_tinseth(self):
-        return sum([x.ibu_tinseth for x in self.hops])
+        return sum(x.ibu_tinseth for x in self.recipehop_set.all())
 
     @property
     def srm(self):
-        color_total = sum([x.srm for x in self.fermentables])
+        color_total = sum(x.lovibond_contributed
+                          for x in self.recipefermentable_set.all())
         return 1.4922*(color_total**0.6859)
 
     @property
@@ -293,11 +303,20 @@ class RecipeFermentable(CustomModel):
         return float(100 * self.quantity / self.recipe.fermentable_weight)
 
     @property
-    def srm(self):
+    def lovibond_contributed(self):
         srm_calc = (float(self.fermentable.lovibond)
                     * float(self.quantity) / self.recipe.final_volume)
         return round(srm_calc, 1)
 
+    @property
+    def ferm_yield(self):
+        potential_yield = self.quantity * (self.fermentable.potential-1) * 1000
+
+        if self.fermentable.fermentable_type == 3:
+            return potential_yield
+        else:
+            return potential_yield * (self.recipe.efficiency/100)
+
 
 class Hop(CustomIngredient):
     uses = {
@@ -345,22 +364,31 @@ class RecipeHop(CustomModel):
             4: 1.4,  # CO2 Extract
         }
 
-        ibu = 0
+        hop_bonus = type_bonus[self.hop.hop_type]
 
-        average_wort_sg = (((self.recipe.pre_boil_sg - 1)
+        average_wort_sg = (((self.recipe.pre_boil_sg-1)
-                           + (self.recipe.original_sg - 1)) / 2)
+                           + (self.recipe.original_sg-1)) / 2)
 
         if self.use == 1:
-            conc = (((float(self.hop.alpha) / 100)
+            conc = (float((self.hop.alpha/100) * self.quantity)
-                    * float(self.quantity))
+                    * 7490/self.recipe.final_volume)
-                    * 7490 / self.recipe.final_volume)
+            util = (hop_bonus*1.65*0.000125**average_wort_sg
-            util = ((type_bonus[self.hop.hop_type]
+                    * ((1-2.71828182845904**(-0.04*self.time)) / 4.15))
-                    * 1.65 * (0.000125**average_wort_sg))
-                    * ((1-2.71828182845904**(-0.04 * self.time))/4.15))
             ibu = conc * util
+        else:
+            ibu = 0
 
         return float(ibu)
 
+    @property
+    def trub_volume(self):
+        if self.hop.hop_type == 1:
+            return self.recipe.equipment.pellet_hop_trub
+        elif self.hop.hop_type in [2, 3]:
+            return self.recipe.equipment.leaf_hop_trub
+        else:
+            return 0
+
 
 class Misc(CustomIngredient):
     uses = {

beer/templates/beer/recipe.html

@@ -24,7 +24,7 @@ font-size: .8em;
 {% block jumbotronsub %}
 
   <div class="row">
-    <div class="col-lg d-flex justify-content-between" style="border:1px solid #cecece; margin-right:.5em; margin-left:.5em">
+    <div class="col-lg d-flex justify-content-between">
       <div>
         <div class="container-beer"><img src="{% static "beer_back.png" %}" alt="" class="img-responsive d-none d-sm-block"></div>
       </div>
@@ -37,7 +37,7 @@ font-size: .8em;
           <dd>All Grain</dd>
         </dl>
     </div>
-    <div class="col-lg-4" style="border:1px solid #cecece; margin-right:.5em; margin-left:.5em">
+    <div class="col-lg-4">
       <div class="d-flex justify-content-between bg-dark text-white">
         <div class="text-truncate ms-1 my-1">{{ recipe.equipment.name }}</div>
         <div>
@@ -59,7 +59,7 @@ font-size: .8em;
         <dd>{{ recipe.efficiency|floatformat:2 }} %</dd>
       </dl>
     </div>
-    <div class="col-xl-3" style="border:1px solid #cecece; margin-right:.5em; margin-left:.5em">
+    <div class="col-xl-3">
       Style Data
     </div>
   </div>
@@ -76,7 +76,7 @@ font-size: .8em;
       <div class="col-md">
         <div class="container-fluid">
           <div class="d-flex justify-content-between bg-dark text-white">
-            <div class="ms-2 my-1">Fermentables ({{ fermentable_weight|floatformat:2 }} lbs)</div>
+            <div class="ms-2 my-1">Fermentables ({{ recipe.fermentable_weight|floatformat:2 }} lbs)</div>
             <div>
               <button type="button" class="btn btn-dark btn-sm"><b>%</b></button>
               <button type="button" class="btn btn-dark btn-sm"><b>OG</b></button>
@@ -115,7 +115,7 @@ font-size: .8em;
       <div class="col-md">
         <div class="container-fluid">
           <div class="d-flex justify-content-between bg-dark text-white">
-            <div class="ms-2 my-1">Hops ({{ hop_weight|floatformat:2 }} oz)</div>
+            <div class="ms-2 my-1">Hops ({{ recipe.hop_weight|floatformat:2 }} oz)</div>
             <div>
               <button type="button" class="btn btn-dark btn-sm"><b>IBU</b></button>
               <button type="button" class="btn btn-dark btn-sm"><i class="fa fa-plus"></i><b>ADD</b></button>

beer/views.py

@@ -46,8 +46,6 @@ def view_recipe(request, recipe_id):
 
     context = {
         'recipe': recipe,
-        'fermentable_weight': sum([x.quantity for x in recipe.fermentables]),
-        'hop_weight': sum([x.quantity for x in recipe.hops]),
     }
 
     return render(request, 'beer/recipe.html', context)