75 lines
3.3 KiB
Python
75 lines
3.3 KiB
Python
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import pandas as pd
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import numpy as np
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import scipy.sparse as sparse
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import surprise as sp
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import time
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from collections import defaultdict
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from itertools import chain
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def data_to_csr(train_read, test_read):
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train_read.columns=['user', 'item', 'rating', 'timestamp']
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test_read.columns=['user', 'item', 'rating', 'timestamp']
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# Let's build whole dataset
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train_and_test=pd.concat([train_read, test_read], axis=0, ignore_index=True)
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train_and_test['user_code'] = train_and_test['user'].astype("category").cat.codes
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train_and_test['item_code'] = train_and_test['item'].astype("category").cat.codes
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user_code_id = dict(enumerate(train_and_test['user'].astype("category").cat.categories))
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user_id_code = dict((v, k) for k, v in user_code_id.items())
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item_code_id = dict(enumerate(train_and_test['item'].astype("category").cat.categories))
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item_id_code = dict((v, k) for k, v in item_code_id.items())
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train_df=pd.merge(train_read, train_and_test, on=list(train_read.columns))
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test_df=pd.merge(test_read, train_and_test, on=list(train_read.columns))
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# Take number of users and items
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(U,I)=(train_and_test['user_code'].max()+1, train_and_test['item_code'].max()+1)
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# Create sparse csr matrices
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train_ui = sparse.csr_matrix((train_df['rating'], (train_df['user_code'], train_df['item_code'])), shape=(U, I))
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test_ui = sparse.csr_matrix((test_df['rating'], (test_df['user_code'], test_df['item_code'])), shape=(U, I))
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return train_ui, test_ui, user_code_id, user_id_code, item_code_id, item_id_code
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def get_top_n(predictions, n=10):
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# Here we create a dictionary which items are lists of pairs (item, score)
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top_n = defaultdict(list)
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for uid, iid, true_r, est, _ in predictions:
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top_n[uid].append((iid, est))
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result=[]
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# Let's choose k best items in the format: (user, item1, score1, item2, score2, ...)
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for uid, user_ratings in top_n.items():
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user_ratings.sort(key=lambda x: x[1], reverse=True)
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result.append([uid]+list(chain(*user_ratings[:n])))
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return result
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def ready_made(algo, reco_path, estimations_path):
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reader = sp.Reader(line_format='user item rating timestamp', sep='\t')
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trainset = sp.Dataset.load_from_file('./Datasets/ml-100k/train.csv', reader=reader)
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trainset = trainset.build_full_trainset() # <class 'surprise.trainset.Trainset'> -> it is needed for using Surprise package
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testset = sp.Dataset.load_from_file('./Datasets/ml-100k/test.csv', reader=reader)
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testset = sp.Trainset.build_testset(testset.build_full_trainset())
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algo.fit(trainset)
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antitrainset = trainset.build_anti_testset() # We want to predict ratings of pairs (user, item) which are not in train set
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print('Generating predictions...')
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predictions = algo.test(antitrainset)
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print('Generating top N recommendations...')
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top_n = get_top_n(predictions, n=10)
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top_n=pd.DataFrame(top_n)
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top_n.to_csv(reco_path, index=False, header=False)
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print('Generating predictions...')
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predictions = algo.test(testset)
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predictions_df=[]
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for uid, iid, true_r, est, _ in predictions:
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predictions_df.append([uid, iid, est])
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predictions_df=pd.DataFrame(predictions_df)
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predictions_df.to_csv(estimations_path, index=False, header=False)
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