word_count_engine.py

def word_count_engine(doc: str):
    words = {} 
    word = [] 
    pos = 0
    result = [] 
    
    # build word list and frequency
    for i, c in enumerate(doc.lower()): 
        if c >= 'a' and c <= 'z': 
            word.append(c) 
        elif c == '\'' or word == []:
            continue
        elif words.get(''.join(word)) is None: 
            words[''.join(word)] = [pos, 1]
            word = [] 
            pos += 1 
        else: 
            words[''.join(word)][1] += 1 
            word = []

        # increment word count if done scanning doc
        if i + 1 == len(doc) and words.get(''.join(word)):
            words[''.join(word)][1] += 1
    
    # insert sort into results list
    for k, v in words.items(): 
        if result == []: 
            result.append((k, v)) 
        else: 
            for i, item in enumerate(result): 
                 if v[1] > item[1][1]: 
                     result.insert(i, (k, v)) 
                     break 
                 elif item[1][1] == v[1] and v[0] < item[1][0]: 
                     result.insert(i, (k, v)) 
                     break 
                 elif i == len(result) - 1: 
                     result.append((k, v)) 
                     break

    result = [[k[0], str(k[1][1])] for k in result]
    return result