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Mann Patel
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recommondation-engine/example1.py
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recommondation-engine/example1.py
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import pandas as pd
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import numpy as np
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from sklearn.feature_extraction.text import TfidfVectorizer
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from sklearn.metrics.pairwise import cosine_similarity
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'''
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Recommender system using content-based filtering
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'''
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class Recommender:
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def __init__(self):
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# Initialize data structures
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self.products_df = None
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self.user_profiles = {}
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self.tfidf_matrix = None
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self.tfidf_vectorizer = None
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self.product_indices = None
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def load_products(self, products_data):
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"""
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Load product data into the recommender system
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products_data: list of dictionaries with product info (id, name, description, category, etc.)
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"""
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self.products_df = pd.DataFrame(products_data)
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# Create a text representation for each product (combining various features)
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self.products_df['content'] = (
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self.products_df['category'] + ' ' +
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self.products_df['name'] + ' ' +
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self.products_df['description']
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)
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# Initialize TF-IDF vectorizer to convert text to vectors
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self.tfidf_vectorizer = TfidfVectorizer(
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stop_words='english',
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max_features=5000, # Limit features to avoid sparse matrices
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ngram_range=(1, 2) # Use both unigrams and bigrams
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)
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# Compute TF-IDF matrix
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self.tfidf_matrix = self.tfidf_vectorizer.fit_transform(self.products_df['content'])
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# Create a mapping from product_id to index
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self.product_indices = pd.Series(
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self.products_df.index,
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index=self.products_df['product_id']
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).drop_duplicates()
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def track_user_click(self, user_id, product_id):
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"""
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Track user clicks on products to build user profiles
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"""
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if user_id not in self.user_profiles:
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self.user_profiles[user_id] = {
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'clicks': {},
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'category_weights': {
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'electronics': 0,
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'school supplies': 0,
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'rental place': 0,
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'furniture': 0
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}
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}
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# Get the clicked product's index and details
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if product_id in self.product_indices:
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product_idx = self.product_indices[product_id]
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product_category = self.products_df.iloc[product_idx]['category']
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# Update click count
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if product_id in self.user_profiles[user_id]['clicks']:
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self.user_profiles[user_id]['clicks'][product_id] += 1
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else:
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self.user_profiles[user_id]['clicks'][product_id] = 1
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# Update category weight
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self.user_profiles[user_id]['category_weights'][product_category] += 1
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def get_user_profile_vector(self, user_id):
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"""
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Generate a user profile vector based on their click history
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"""
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if user_id not in self.user_profiles or not self.user_profiles[user_id]['clicks']:
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# Return a zero vector if no click history
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return np.zeros((1, self.tfidf_matrix.shape[1]))
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# Create a weighted average of all clicked products' TF-IDF vectors
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clicked_product_vectors = []
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weights = []
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for product_id, click_count in self.user_profiles[user_id]['clicks'].items():
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if product_id in self.product_indices:
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product_idx = self.product_indices[product_id]
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product_category = self.products_df.iloc[product_idx]['category']
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category_weight = self.user_profiles[user_id]['category_weights'][product_category]
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# Weight is based on both click count and category preference
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weight = click_count * (1 + 0.5 * category_weight)
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weights.append(weight)
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clicked_product_vectors.append(self.tfidf_matrix[product_idx])
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# Normalize weights
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weights = np.array(weights) / np.sum(weights)
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# Compute weighted average
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user_profile = np.zeros((1, self.tfidf_matrix.shape[1]))
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for i, vector in enumerate(clicked_product_vectors):
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user_profile += weights[i] * vector.toarray()
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return user_profile
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def recommend_products(self, user_id, n=5, category_filter=None):
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"""
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Recommend products to a user based on their profile
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user_id: ID of the user
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n: Number of recommendations to return
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category_filter: Optional filter to limit recommendations to a specific category
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"""
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# Get user profile vector
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user_profile = self.get_user_profile_vector(user_id)
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# If user has no profile, recommend popular products (not implemented)
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if np.sum(user_profile) == 0:
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return self._get_popular_products(n, category_filter)
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# Calculate similarity scores
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sim_scores = cosine_similarity(user_profile, self.tfidf_matrix)
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sim_scores = sim_scores.flatten()
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# Create a DataFrame for easier filtering
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recommendations_df = pd.DataFrame({
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'product_id': self.products_df['product_id'],
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'score': sim_scores,
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'category': self.products_df['category']
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})
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# Filter out products that the user has already clicked on
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if user_id in self.user_profiles and self.user_profiles[user_id]['clicks']:
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clicked_products = list(self.user_profiles[user_id]['clicks'].keys())
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recommendations_df = recommendations_df[~recommendations_df['product_id'].isin(clicked_products)]
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# Apply category filter if provided
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if category_filter:
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recommendations_df = recommendations_df[recommendations_df['category'] == category_filter]
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# Sort by similarity score and get top n recommendations
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recommendations_df = recommendations_df.sort_values('score', ascending=False).head(n)
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# Return recommended product IDs
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return recommendations_df['product_id'].tolist()
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def _get_popular_products(self, n=5, category_filter=None):
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"""
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Return popular products when a user has no profile
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(This would typically be implemented with actual popularity metrics)
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"""
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filtered_df = self.products_df
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if category_filter:
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filtered_df = filtered_df[filtered_df['category'] == category_filter]
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# Just return random products for now (in a real system you'd use popularity metrics)
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if len(filtered_df) >= n:
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return filtered_df.sample(n)['product_id'].tolist()
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else:
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return filtered_df['product_id'].tolist()
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def recommend_by_category_preference(self, user_id, n=5):
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"""
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Recommend products based primarily on the user's category preferences
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"""
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if user_id not in self.user_profiles:
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return self._get_popular_products(n)
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# Get the user's most clicked category
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category_weights = self.user_profiles[user_id]['category_weights']
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# If no category has been clicked, return popular products
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if sum(category_weights.values()) == 0:
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return self._get_popular_products(n)
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# Sort categories by number of clicks
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sorted_categories = sorted(
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category_weights.items(),
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key=lambda x: x[1],
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reverse=True
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)
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recommendations = []
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remaining = n
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# Allocate recommendations proportionally across categories
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for category, weight in sorted_categories:
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if weight > 0:
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# Allocate recommendations proportionally to category weight
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category_allocation = max(1, int(remaining * (weight / sum(category_weights.values()))))
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if category_allocation > remaining:
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category_allocation = remaining
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# Get recommendations for this category
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category_recs = self.recommend_products(user_id, category_allocation, category)
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recommendations.extend(category_recs)
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# Update remaining slots
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remaining -= len(category_recs)
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if remaining <= 0:
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break
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# If we still have slots to fill, add general recommendations
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if remaining > 0:
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general_recs = self.recommend_products(user_id, remaining)
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# Filter out duplicates
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general_recs = [rec for rec in general_recs if rec not in recommendations]
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recommendations.extend(general_recs[:remaining])
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return recommendations
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exported = Recommender()
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