python - 数据验证：在选择正确的输入之前，如何让我的程序发出错误？

Question

print "Welcome to aa47's Voice Mail Message Program!"
print "You are currently using a"+ " " + platform.system()+ " Operating System"
g = raw_input("What gender would you prefer Male or Female? (Please press m or f)")

我相信我需要创建一个循环，但我不确定如何

if g == "m":
    print "You have chosen the Gender Male"
elif g == "f":
    print "You have chosen the Gender Female"
else:
    print "You have entered an invalid choice"
    print "Program restarting"
    execfile ("my python project.py")

Answer 1

你可能想把它包装在一个循环中

valid_gender = False
while not valid_gender:
    g = raw_input("What gender would you prefer Male or Female? (Please press m or f)")
    if g == "m":
        print "You have chosen the Gender Male"
        valid_gender=True
    elif g == "f":
        print "You have chosen the Gender Female"
        valid_gender = True
    else:
        print "You have entered an invalid choice"