Comparing NLP Techniques for Scalable Product Search

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import json
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import requests
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url = "https://asos2.p.rapidapi.com/categories/list"
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headers = {
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   "x-rapidapi-key": "YOUR_RAPIDAPI_KEY",
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   "x-rapidapi-host": "asos2.p.rapidapi.com",
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}
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response = requests.request("GET", url, headers=headers)
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categories = json.loads(response.text)
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for category in categories:a
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   url = f"https://asos2.p.rapidapi.com/products/v2/list/{category['id']}"
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   response = requests.request("GET", url, headers=headers)
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   products = json.loads(response.text)
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   # Store products in GCS
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   bucket = os.environ.get('GS_BUCKET_NAME')
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   product_filename = f"products_{datetime.now().strftime('%H%m%S')}.json"
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   write(bucket, str(date.today()) + "/" + product_filename, products)

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from pyspark.ml.feature import RegexTokenizer, StopWordsRemover
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# Instantiate and set input and output column parameters
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regexTokenizer = RegexTokenizer(
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   inputCol="product_name", outputCol="words", pattern="\\W"
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)
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remover = StopWordsRemover(inputCol="words", outputCol="filtered")
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# Transform the data
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regexTokenized = regexTokenizer.transform(df)
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removedStopWords = remover.transform(regexTokenized)

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import json
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from pymongo import MongoClient
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client = MongoClient(
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   "mongodb://<username>:<password>@cluster0.mongodb.net/test?retryWrites=true&w=majority"
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)
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db = client.get_database("product_db")
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products = db.products
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# Fetch data from GCS
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for product in gcs_data:
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   products.insert_one(product)

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from pyspark.ml.feature import IDF, HashingTF
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hashingTF = HashingTF(inputCol="filtered", outputCol="rawFeatures", numFeatures=20)
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featurizedData = hashingTF.transform(removedStopWords)
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idf = IDF(inputCol="rawFeatures", outputCol="features")
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idfModel = idf.fit(featurizedData)
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rescaledData = idfModel.transform(featurizedData)

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from pyspark.ml.feature import Word2Vec
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word2Vec = Word2Vec(
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   vectorSize=300, minCount=0, inputCol="filtered", outputCol="features"
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)
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model = word2Vec.fit(removedStopWords)
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result = model.transform(removedStopWords)

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# Compute IDF values for each term
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# Compute term frequency in each document for each term
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# For each query term, do:
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# For each document containing the term do:
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# Compute BM25 Score
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# Sort documents by score

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def stemming(words):
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   ps = PorterStemmer()
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   result = []
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   for w in words:
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       root_word = ps.stem(w)
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       result.append(root_word)
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   return result
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stemming_udf = udf(lambda x: stemming(x), ArrayType(elementType=StringType()))
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preprocessed_data = preprocessed_data.withColumn(
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"tokens", stemming_udf("filtered_words")
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)

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words = preprocessed_data.select(explode("tokens").alias("word"))
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total_unique_words = words.select("word").distinct().count()
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total_words = words.count()

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id_str = concat_ws("", col("_id").cast(StringType()))
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word_count_df = (
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   preprocessed_data.select("_id", explode("tokens").alias("word"))
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   .groupBy("word", "_id")
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   .agg(size(collect_list("word")).alias("occurrence"))
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   .groupBy("word")
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   .agg(
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       map_from_entries(collect_list(struct(id_str.alias("id"), "occurrence"))).alias(
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           "documents"
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       )
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   )
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   .withColumnRenamed("word", "_id")
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).rdd.map(lambda row: (row["_id"], row["documents"]))
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inverted_index = word_count_df.collectAsMap()

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doc_length_df = (
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   preprocessed_data.select("_id", size("tokens").alias("length"))
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   .groupBy("_id")
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   .agg(sum(col("length")).alias("doc_length"))
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   .withColumn("_id", concat_ws("", col("_id").cast(StringType())))
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   .rdd.map(lambda row: (row["_id"], row["doc_length"]))
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)
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doc_length = doc_length_df.collectAsMap()
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doc_length["word_counter"] = total_unique_words
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doc_length["doc_counter"] = total_words
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unique_word_count_df = preprocessed_data.select(
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   "_id",
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   size(array_distinct("tokens")).alias("num_unique_words"),
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).withColumn("_id", concat_ws("", col("_id").cast(StringType()))).rdd.map(lambda row: (row["_id"], row["num_unique_words"]))
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unique_word = unique_word_count_df.collectAsMap()

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def bm25(doc_length,
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  inverted_index, 
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   unique_word, 
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   word_counter, 
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   doc_counter, 
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   query):
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   k1 = 1.2
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   b = 0.75
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   k2 = 100
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   N = len(doc_length) - 2
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   avgdl = doc_length["doc_counter"] / N
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   score = defaultdict(int)
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   for word in query:
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       if word in inverted_index:
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           n = len(inverted_index[word])
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           idf = math.log((N - n + 0.5) / (n + 0.5))
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           for doc, freq in inverted_index[word].items():
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               f = freq
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               qf = query.count(word)
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               dl = doc_length[doc]
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               K = k1 * ((1 - b) + b * (float(dl) / float(avgdl)))
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               R1 = idf * ((f * (k1 + 1)) / (f + K))
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               R2 = (qf * (k2 + 1)) / (qf + k2)
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               R = R1 * R2
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               score[doc] += R
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       else:
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           Continue
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   return score

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from sentence_transformers import SentenceTransformer
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model = SentenceTransformer('bert-base-nli-mean-tokens')
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sentence_embeddings = model.encode(data['product_name'])