如何在 python 中对计算器进行输入检查？

Question

print("Welcome to the Kinetic Energy and Gravitational Potential Energy Calculator")
print("Which Calculator would you like to access?")

Choice = str(input("Type in KE for Kinetic Energy and GPE for Gravitational Potential Energy:"))

while Choice != "KE" or "GPE":
    print("Error. You have not entered a valid choice. Please type KE or GPE.")
    Choice = str(input("Type in KE for Kinetic Energy and GPE for Gravitational Potential Energy:"))


while Choice == "KE":
    print("You have chosen the Kinetic Energy Calculator.")
    mass = float(input("Type in the mass of the object in kilograms (kg):"))
    velocity = float(input("Type in the velocity of the object in metres per second (m/s):"))
    result = 0.5*mass*(velocity**2)
    print("The KE is:", result, "J(Joules)")
    Choice = str(input("Type in KE for Kinetic Energy and GPE for Gravitational Potential Energy:"))

while Choice == "GPE":
    print("You have chosen the Gravitational Potential Energy Calculator.")
    mass = float(input("Type in the mass of the object in kilograms (kg):"))
    height = float(input("Type in the height at which the object is in metres (m):"))
    result = 9.81*mass*height
    print("The GPE is:", result, "J(Joules)")
    Choice = str(input("Type in KE for Kinetic Energy and GPE for Gravitational Potential Energy:"))

我试过使用"or"所以检查可以包括'KE'和'GPE'，但是当你运行程序时，即使我输入KE或GPE ，第一个 while 循环继续！我怎样才能让它发挥作用？

Answer 1

问题出在你的情况。由于"GPE"在逻辑上是True（非空字符串在逻辑上是True），while循环条件总是True，不管选择什么

变化：

Choice != "KE" or "GPE"

至：

Choice != "KE" and Choice != "GPE"

或：

Choice not in ["KE","GPE"]

如何在 python 中对计算器进行输入检查？

How to put an input check for a calculator in python?

python

input

calculator

while-loop