python实现简单温度转换的方法

def c2f(t):
    return (t*9/5.0)+32
def c2k(t):
    return t+273.15
def f2c(t):
    return (t-32)*5.0/9
def f2k(t):
    return (t+459.67)*5.0/9
def k2c(t):
    return t-273.15
def k2f(t):
    return (t*9/5.0)-459.67
def get_user_input():
    user_input = 0
    while type(user_input) != type(1.0):
        user_input = raw_input("Enter degrees to convert: ")
        try:
            user_input = float(user_input)
        except:
            print user_input + " is not a valid entry"
    return user_input
def main():
    menu = "\nTemperature Convertor\n\n"+\
        "1. Celsius to Fahrenheit\n"+\
        "2. Celsius to Kelvin\n"+\
        "3. Fahrenheit to Celsius\n"+\
        "4. Fahrenheit to Kelvin\n"+\
        "5. Kelvin to Celsius\n"+\
            "6. Kelvin to Fahrenheit\n"+\
        "7. Quit"
    user_input = 0
    while user_input != 7:
        print menu
        user_input = raw_input("Please enter a valid selection: ")
        try:
            user_input = int(user_input)
        except:
            print user_input + " is not a valid selction, please try again\n"
        if user_input == 1:
            t = get_user_input()
            print str(t) + " degree Celsius is " + str((c2f(t))) + " degree Fahrenheit"
        elif user_input == 2:
            t = get_user_input()
            print str(t) + " degree Celsius is " + str((c2k(t))) + " degree Kelvin"
        elif user_input == 3:
            t = get_user_input()
            print str(t) + " degree Fahrenheit is " + str((f2c(t))) + " degree Celsius"
        elif user_input == 4:
            t = get_user_input()
            print str(t) + " degree Fahrenheit is " + str((f2K(t))) + " degree Kelvin"
        elif user_input == 5:
            t = get_user_input()
            print str(t) + " degree Kelvin is " + str((k2c(t))) + " degree Celsius"
        elif user_input == 6:
            t = get_user_input()
            print str(t) + " degree Kelvin is " + str((k2f(t))) + " degree Fahrenheit"
        elif user_input == 7:
            quit()
        else:
            print str(user_input) + " is not a valid selection, please try again\n"
if __name__ == "__main__":
    main()