import math

def stats(lista):
    if not lista:       #lista is empty
        return 0,0
    mean = 0
    var = 0
    for element in lista:
        mean += element
    for element in lista:
        var += (element-mean)**2
    return mean/len(lista), math.sqrt(var/len(lista))


def minus(string1, string2):
    my_set = set(string1)
    my_other = set(string2)
    return "".join(my_set - my_other)

def count(filename):
    with open(filename) as infile:
        count_line = 0
        count_word = 0
        count_char = 0
        for line in infile:
            count_line +=1
            line = line.strip()
            count_word += len(line.split())
            count_char += len(line)
    return count_line, count_word, count_char

def pretty_print():
    filename = input("Enter the name of a file: ")
    cl, cw, cc = count(filename)
    print( "There are {} lines, {} words, and {} characters in the file {}.".format(
        cl, cw, cc, filename))
    return