ValueError 和 ZeroDivisionError

Question

我正在尝试执行计算 ((x/y) + z) 并解释 2 个错误：ValueError 和 ZeroDivisionError.

但是，我很难理解如何将这 2 个错误编码到我的程序中。我想我已经 ValueError 想通了，但还没有 ZeroDivisionError。这是我到目前为止所拥有的。不好意思弄乱了rn....

user_input = (input("Enter three numbers separated by a space: ")).split()
x = int(user_input[0])
y = int(user_input[1])
z = int(user_input[2])
  
def calculate(x, y, z):
    '''calculate (x/y)+z'''
    c = ((x/y) + z) if y != 0 else print("Second input value cannot be 0")
    return c

try:
    input_values_str = str(user_input)
    c = ((x/y) + z)
    for val in input_values_str:
        if len(user_input) == 3:
            print("Correct number of values.")
        else:
            print("Incorrect number of values entered.")

except ValueError:
    print(user_input," is not valid input.")

except ZeroDivisionError:
    y = 0
    print("Second value cannot be 0")
print("Formula: ({}/{}) + {} = {}".format(x, y, z, calculate(x, y, z)))

Answer 1

我根本不明白你为什么需要 try/except/except 块。您已经在 calculate 方法中检查 y=0，并且您已经知道您的输入有效，否则 split 和转换 int() 会失败。那里的 for 循环一遍又一遍地打印相同的输出字符串。如果你把所有这些都去掉，你的代码似乎可以正常工作

try:
    file_name = open('/tmp/data.txt', 'r')
except FileNotFoundError:
    print("File could not be found. Please check spelling of file name!")
    sys.exit()

#Read lines in file
Lines = file_name.read().splitlines()

user_input = (input("Enter three numbers separated by a space: ")).split()
x = int(user_input[0])
y = int(user_input[1])
z = int(user_input[2])

def calculate(x, y, z):
    '''calculate (x/y)+z'''
    c = ((x / y) + z) if y != 0 else print("Second input value cannot be 0")
    return c

print("Formula: ({}/{}) + {} = {}".format(x, y, z, calculate(x, y, z)))

Answer 2

您引发异常以查看 y == 0 是否存在，但第一个值 (x) 也不能为 0。并且您需要将 2 个 if 语句放在 c = ...

之前

试试这个：

user_input = (input("Enter three numbers separated by a space: ")).split()
x = int(user_input[0])
y = int(user_input[1])
z = int(user_input[2])

def calculate(x, y, z):
    '''calculate (x/y)+z'''
    if y == 0 or x == y:
        print("Invalid Input")
    else:
        c = ((x/y) + z)
        return c

try:
    input_values_str = str(user_input)
    c = ((x/y) + z)
    for val in input_values_str:
        if len(user_input) == 3:
            print("Correct number of values.")
        else:
            print("Incorrect number of values entered.")

except ValueError:
    print(user_input," is not valid input.")

except ZeroDivisionError:
    y = 0
    x = 0
    print("Second value cannot be 0. First Value cannot be 0")
    print("Formula: ({}/{}) + {} = {}".format(x, y, z, calculate(x, y, z)))

Answer 3

我只是调整了您的代码以满足您的期望，并且易于理解。

user_input = (input("Enter three numbers separated by a space: ")).split()
x = int(user_input[0])
y = int(user_input[1])
z = int(user_input[2])

try:
    c = ((x/y) + z) if y != 0 else print("Second input value cannot be 0")
except ValueError:
    print(user_input," is not valid input.")
print("Formula: ({}/{}) + {} = {}".format(x, y, z, c))

Answer 4

恭喜学习 Python！我认为您的代码有点混乱。我将 post 你的版本加上我的一些评论，然后我将 post 一个我认为更好地实现你想要做的事情的清理版本。希望它具有指导意义。有更优雅的方法可以做到这一点，但我尽量保留你的结构。

您的代码：

user_input = (input("Enter three numbers separated by a space: ")).split()
x = int(user_input[0])
y = int(user_input[1])
z = int(user_input[2])

def calculate(x, y, z):
    c = ((x/y) + z) if y != 0 else print("Second input value cannot be 0")  #Why do you need a ZeroDivisonError check below when you check for Zero here?
return c

try:
    input_values_str = str(user_input) # why are you taking an input here? Did you take the input above? And why convert it back into a string?
    c = ((x/y) + z)
    for val in input_values_str: # Why are you iterating through string? You're basically checking 3 times if the length of your string is 3 characters
        if len(user_input) == 3:
            print("Correct number of values.")
        else:
            print("Incorrect number of values entered.")

except ValueError:
    print(user_input," is not valid input.")

except ZeroDivisionError:
    y = 0 # why set y back to zero in the event oa ZeroDivisonError? Won't that just create a ZeroDivison Error? Might make more sense to get a new input from the user
    print("Second value cannot be 0")
print("Formula: ({}/{}) + {} = {}".format(x, y, z, calculate(x, y, z))) # if the objective is to only print something, why not do it in the calculate function? Then we can contain your ZeroDivisionError in their and request a new y

我的代码：

def calculate(x, y, z):
    try:
        solution = (x/y) + z
        print(f"Formula: ({x}/{y}) + {z} = {solution}")

    except ZeroDivisionError:
        y = int(input("2nd value cannot be a Zero. Please input a new y value: "))
        calculate(x, y, z)

try:
    user_input = (input("Enter three numbers separated by a space: ")).split()

    while len(user_input) != 3:
        print("Incorrect number of values entered.")
        user_input = (input("Enter three numbers separated by a space: ")).split()

    x = int(user_input[0])
    y = int(user_input[1])
    z = int(user_input[2])

    calculate(x, y, z)

except ValueError:
    print(user_input," is not valid input.")

ValueError 和 ZeroDivisionError

ValueError and ZeroDivisionError

python

valueerror