feat: function which returns top three most used word in a text

src/codewars/kata_most_words_used.py

@@ -1,2 +1,50 @@
-def top_3_words(text):
-    return None
+def top_3_words(text: str) -> list:
+    """Given a string of text (possibly with punctuation and line-breaks),
+    returns an array of the top-3 most occurring words, in descending order
+    of the number of occurrences.
+
+    Args:
+        text (str): Some text
+
+    Returns:
+        list: [most used word, second most used word, third most used word]
+    """
+    text = "".join(
+        c if c.isalpha() or c.isdigit() or c in ("'", " ") else " " for c in text
+    )  # remove invalid characters and replace with whitespace
+    text = text.split()
+
+    word_count = {}
+
+    for word in text:
+        if word in word_count:
+            word_count[word] += 1
+        else:
+            word_count[word] = 1
+
+    top_3 = {
+        "first": {"word": None, "amount": 0},
+        "second": {"word": None, "amount": 0},
+        "third": {"word": None, "amount": 0},
+    }
+
+    for word in word_count:
+        if word_count[word] > top_3["first"]["amount"]:
+            top_3["first"]["word"] = word
+            top_3["first"]["amount"] = word_count[word]
+        elif word_count[word] > top_3["second"]["amount"]:
+            top_3["second"]["word"] = word
+            top_3["second"]["amount"] = word_count[word]
+        elif word_count[word] > top_3["third"]["amount"]:
+            top_3["third"]["word"] = word
+            top_3["third"]["amount"] = word_count[word]
+
+    return [
+        x
+        for x in [
+            top_3["first"]["word"],
+            top_3["second"]["word"],
+            top_3["third"]["word"],
+        ]
+        if x is not None
+    ]