NoneType' object has no attribute 'name' - django

Question

I was building wine recommendation system using k means approach in django. I made cluster module in admin and added 3 clusters manually. However, when I am trying to recommend wine to logged in user I get this error.Can you please help:
AttributeError at /reviews/recommendation/
'NoneType' object has no attribute 'name'
I am getting error in line:
User.objects.get(username=request.user.username).cluster_set.first().name
here is the code for view.py
#login_required
def user_recommendation_list(request):
# get request user reviewed wines
user_reviews = Review.objects.filter(user_name=request.user.username).prefetch_related('wine')
user_reviews_wine_ids = set(map(lambda x: x.wine.id, user_reviews))
# get request user cluster name (just the first one righ now)
try:
user_cluster_name = \
User.objects.get(username=request.user.username).cluster_set.first().name
except: # if no cluster assigned for a user, update clusters
update_clusters()
user_cluster_name = \
User.objects.get(username=request.user.username).cluster_set.first().name
# get usernames for other memebers of the cluster
user_cluster_other_members = \
Cluster.objects.get(name=user_cluster_name).users \
.exclude(username=request.user.username).all()
other_members_usernames = set(map(lambda x: x.username, user_cluster_other_members))
# get reviews by those users, excluding wines reviewed by the request user
other_users_reviews = \
Review.objects.filter(user_name__in=other_members_usernames) \
.exclude(wine__id__in=user_reviews_wine_ids)
other_users_reviews_wine_ids = set(map(lambda x: x.wine.id, other_users_reviews))
# then get a wine list including the previous IDs, order by rating
wine_list = sorted(
list(Wine.objects.filter(id__in=other_users_reviews_wine_ids)),
key=lambda x: x.average_rating,
reverse=True
)
return render(
request,
'reviews/user_recommendation_list.html',
{'username': request.user.username,'wine_list': wine_list}
)
and here is the code for suggestions.py
from .models import Review, Wine, Cluster
from django.contrib.auth.models import User
from sklearn.cluster import KMeans
from scipy.sparse import dok_matrix, csr_matrix
import numpy as np
def update_clusters():
num_reviews = Review.objects.count()
update_step = ((num_reviews/100)+1) * 5
if num_reviews % update_step == 0: # using some magic numbers here, sorry...
# Create a sparse matrix from user reviews
all_user_names = map(lambda x: x.username, User.objects.only("username"))
all_wine_ids = set(map(lambda x: x.wine.id, Review.objects.only("wine")))
num_users = len(all_user_names)
ratings_m = dok_matrix((num_users, max(all_wine_ids)+1), dtype=np.float32)
for i in range(num_users): # each user corresponds to a row, in the order of all_user_names
user_reviews = Review.objects.filter(user_name=all_user_names[i])
for user_review in user_reviews:
ratings_m[i,user_review.wine.id] = user_review.rating
# Perform kmeans clustering
k = int(num_users / 10) + 2
kmeans = KMeans(n_clusters=k)
clustering = kmeans.fit(ratings_m.tocsr())
# Update clusters
Cluster.objects.all().delete()
new_clusters = {i: Cluster(name=i) for i in range(k)}
for cluster in new_clusters.values(): # clusters need to be saved before refering to users
cluster.save()
for i,cluster_label in enumerate(clustering.labels_):
new_clusters[cluster_label].users.add(User.objects.get(username=all_user_names[i]))

Answer 1

When you are going to add data in the cluster table at that time you need to insert your current logged in username. For instance,
jadianes, carlos, and lluis
<username>, teus, yasset
...