Merge pull request #36 from MIT-Emerging-Talent/word-frequency-counter

Word frequency counter

solutions/tests/test_word_frequency_counter.py

@@ -0,0 +1,71 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+This is a test module for counting the frequency of words in a given sentence.
+
+Test categories:
+    - Standard cases: typical strings with different lengths
+    - Edge cases: white space input and punctuation handling
+    - Defensive tests: non-string inputs
+
+Created on 01.01.2025
+@author: Ahmad Hamed Dehzad
+"""
+
+import unittest
+from ..word_frequency_counter import word_frequency_counter
+
+
+class TestWordFrequencyCounter(unittest.TestCase):
+    """Test the word_frequency_counter function"""
+
+    def test_empty_string(self):
+        """It should evaluate an empty string to an empty dictionary"""
+        actual = word_frequency_counter("")
+        expected = {}
+        self.assertEqual(actual, expected)
+
+    def test_single_word(self):
+        """It should evaluate a single word correctly"""
+        actual = word_frequency_counter("Hello")
+        expected = {"hello": 1}
+        self.assertEqual(actual, expected)
+
+    def test_multiple_words(self):
+        """It should count the frequency of multiple words"""
+        actual = word_frequency_counter("Hello world hello")
+        expected = {"hello": 2, "world": 1}
+        self.assertEqual(actual, expected)
+
+    def test_case_insensitivity(self):
+        """It should treat words case-insensitively"""
+        actual = word_frequency_counter("Apple apple APPLE")
+        expected = {"apple": 3}
+        self.assertEqual(actual, expected)
+
+    def test_with_punctuation(self):
+        """It should handle punctuation by ignoring it"""
+        actual = word_frequency_counter("Hello, world! Hello.")
+        expected = {"hello": 2, "world": 1}  # Updated expected result
+        self.assertEqual(actual, expected)
+
+    def test_numbers_in_string(self):
+        """It should handle strings with numbers"""
+        actual = word_frequency_counter("123 123 456")
+        expected = {"123": 2, "456": 1}
+        self.assertEqual(actual, expected)
+
+    def test_non_string_input(self):
+        """It should raise a ValueError if the input is not a string"""
+        with self.assertRaises(ValueError):
+            word_frequency_counter(12345)
+
+    def test_with_whitespace(self):
+        """It should handle extra spaces correctly"""
+        actual = word_frequency_counter("   Hello   world   ")
+        expected = {"hello": 1, "world": 1}
+        self.assertEqual(actual, expected)
+
+
+if __name__ == "__main__":
+    unittest.main()

solutions/word_frequency_counter.py

@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+"""
+A module for counting the frequency of words in a given sentence.
+
+Features:
+    - Handles case-insensitivity
+    - Strips punctuation
+    - Validates input as a string
+
+Created on 01.01.2025
+@author: Ahmad Hamed Dehzad
+
+Examples:
+    >>> word_frequency_counter("Hello world hello")
+    {'hello': 2, 'world': 1}
+
+    >>> word_frequency_counter("Hello, world! Hello.")
+    {'hello': 2, 'world': 1}
+"""
+
+import string
+
+
+def word_frequency_counter(sentence: str) -> dict[str, int]:
+    """
+    Counts the frequency of each word in a given sentence.
+
+    Args:
+        sentence (str): A sentence containing words.
+
+    Returns:
+        dict[str, int]: A dictionary where keys are words (case-insensitive)
+        and values are their frequency.
+
+    Raises:
+        ValueError: If the input is not a string.
+    """
+    if not isinstance(sentence, str):
+        raise ValueError("Invalid input: Please enter a text string.")
+
+    # Remove punctuation and split into words
+    cleaned_sentence = sentence.translate(str.maketrans("", "", string.punctuation))
+    words = cleaned_sentence.split()
+
+    # Count word frequencies
+    word_frequencies = {}
+    for word in words:
+        word = word.lower()
+        word_frequencies[word] = word_frequencies.get(word, 0) + 1
+
+    return word_frequencies