gistfile1.py

from fractions import Fraction

def strToNum(string):
    if '/' in string:   #if user entered a fraction
        string = string.split('/')
        return Fraction(int(string[0]), int(string[1]))
    elif '.' in string: #if user entered a decimal
        return float(string)
    else: return int(string)

run = 1
while run:
    coords = []
    for x in range(2):
        coords.append(input("coord {}: ".format(x+1)).split())

    coords = [(strToNum(x), strToNum(y)) for (x, y) in coords]
    
    x1, y1 = coords[0][0], coords[0][1]
    x2, y2 = coords[-1][0], coords[-1][1]

    delta_y = y2 - y1
    delta_x = x2 - x1
    
    print()
    print("∆y = {} - {} = {}".format(y2, y1, delta_y))
    print("∆x = {} - {} = {}".format(x2, x1, delta_x))
    if type(delta_y) != 'Fraction' and type(delta_x) != 'Fraction':
        print("m = {}/{} ≈ {}".format(delta_y, delta_x, float(delta_y/delta_x)))
    else:
        print("m = {} ≈ {}".format(delta_y/delta_x, float(delta_y/delta_x)))
    print()
    cont = input("Another? (y/n): ")
    if cont == 'n':
        run = 0