added text summarizer python

Author: eleensmathew

Python/TextSummarizer/requirements.txt

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+nltk

Python/TextSummarizer/text_summarizer.py

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+import nltk
+nltk.download('punkt_tab')
+nltk.download('stopwords')
+from nltk.corpus import stopwords
+from nltk.tokenize import word_tokenize, sent_tokenize
+import string
+
+
+def summarize_text_nltk(text, num_sentences=3):
+    """
+    Summarizes the input text using a frequency-based method with NLTK.
+
+    Args:
+        text (str): The text to be summarized.
+        num_sentences (int): The desired number of sentences in the summary.
+
+    Returns:
+        str: The summarized text.
+    """
+    if not text:
+        return ""
+    text = " ".join(text.split()) 
+    sentences = sent_tokenize(text)
+    if len(sentences) <= num_sentences:
+        return text
+    stop_words = set(stopwords.words('english'))
+    punctuations = string.punctuation
+    words = word_tokenize(text.lower())
+    clean_words = [word for word in words if word.isalnum() and word not in stop_words]
+    word_freq = {}
+    for word in clean_words:
+        word_freq[word] = word_freq.get(word, 0) + 1
+    max_freq = max(word_freq.values())
+    for word in word_freq:
+        word_freq[word] = word_freq[word] / max_freq
+    sentence_scores = {}
+    for sentence in sentences:
+        for word in word_tokenize(sentence.lower()):
+            if word in word_freq:
+                if sentence not in sentence_scores:
+                    sentence_scores[sentence] = word_freq[word]
+                else:
+                    sentence_scores[sentence] += word_freq[word]
+    sorted_sentences = sorted(sentence_scores.items(), key=lambda item: item[1], reverse=True)
+    summary_sentences = [sentence for sentence, score in sorted_sentences[:num_sentences]]
+    final_summary = []
+    selected_sentences_set = set(summary_sentences)
+    
+    for sentence in sentences:
+        if sentence.strip() in selected_sentences_set:
+             final_summary.append(sentence)
+
+    return " ".join(final_summary)
+
+input_text = """
+Hacktoberfest is a month-long celebration of open source software, where developers from around 
+the world contribute to various projects. It encourages participation in the open source community 
+and helps improve software quality through collaborative efforts. Participants can earn rewards by 
+making contributions, such as pull requests, to eligible repositories on GitHub.
+"""
+
+summary = summarize_text_nltk(input_text, num_sentences=1)
+
+print(input_text)
+
+print(summary)