import requests
import csv

def download_files():
    #This function creates two .dat files necessary for further calculations

    weather_source = requests.get('http://codekata.com/data/04/weather.dat')
    football_source = requests.get('http://codekata.com/data/04/football.dat')

    with open('weather.dat', 'wb') as f:
        f.write(weather_source.content)

    with open('football.dat', 'wb') as f:
        f.write(football_source.content)

def smallest_temperature_difference():
    weather = open('weather.dat')

    weather_data_list =[]

    for line in weather:
        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)