import glob

filenames = glob.glob('*.dat')

for file in filenames:
    data = open(file)
    if file.startswith('weather'):
        weather_data_list = []

        for line in data:
            weather_data_list += [line.split()]

        separate_days_data = [x for x in weather_data_list[2:]]
        temperatures_list = [x[:3] for x in separate_days_data[:-1]]
        numeric_lists = [[elem.replace('*', '') for elem in lst] for lst in
                         temperatures_list]  # Remove asterisks from string
        values = [[int(x) for x in sublist] for sublist in numeric_lists]
        max_temperatures = [x[1] for x in values]
        min_temperatures = [x[2] for x in values]
        subtraction_results = [x - y for x, y in zip(max_temperatures, min_temperatures)]
        day_with_smallest_temp_spread = subtraction_results.index(min(subtraction_results)) + 1

        print('Day with smallest temperature spread is day number', day_with_smallest_temp_spread)