我如何在python中多次处理值错误异常[重复]

Question

我正在尝试编写一个 BMI 计算器。我试图确保用户输入只是一个浮点数，所以我使用了except，但我无法让它循环检查。

def error_handeling():
    try:
        weight = float(input("enter your weight in KG : "))
    except ValueError:
        weight = float(input("enter your REAL weight in KG : "))

for i in range(100):
    error_handeling()

while weight < 2.0:
    print("enter a valid weight")
    weight = float(input("enter your weight in KG : "))
    if False:
        break


height = float(input("enter your height in Meters: "))


while height < 0.5 or height > 2.2:
    print("enter a valid height ")
    height = float(input("enter your height in meters : "))
    if False:
        break


BMI = weight / (height**2.0)

print("your bmi is : " + str(BMI))

if BMI < 18.5:
    print("you're underweight EAT MORE !!")
if BMI > 18.5:
    print("you're overweight EAT LESS + practise sport !!")
if BMI == 18.5:
    print("you're in perfect weight")

Answer 1

用这个替换你的error_handling函数：

def get_weight():
    while True:
        try:
            weight = float(input("enter your weight in KG : "))
            return weight
        except ValueError:
            print("please enter a valid number.")

并在需要用户体重时致电get_weight。

这样它会一遍又一遍地询问重量，直到用户提供一个好的答案。