import os
import re

def convert_text(s):
    # Removes all characters from string except letters and digits and convert letters to lowercase
    return re.sub("[^a-zA-Z0-9]", " ", s.lower())

def read_texts(dir_path="./Downloads/9sem_data/beatles/"):
    # Reads all files from directory
    if dir_path[-1] != os.path.sep:
        dir_path = dir_path + os.path.sep
    txt_list = []
    for file in os.listdir(dir_path):
        file = dir_path + file
        fin = open(file, 'r', encoding='latin1')
        txt = " ".join(fin.readlines())
        txt = convert_text(txt)
        txt_list.append(txt)
    return txt_list