python - Python 中的异常处理(Try...Except)

Question

我试图在下面的代码中实现 try...except 异常处理。当输入“s4”之类的内容时，我希望出现“非数字值...”的输出。

知道我哪里出错了吗？

import string

import math

def getSqrt(n):
    return math.sqrt(float(n))

s = input("Enter a numerical value: ")

try:
    for i in s:
        if (i.isdigit() or i == "."):
            sType = "nonstr"

    if (sType =="nonstr"):
        print(getSqrt(s))

    else:
        s = "Non numberical value..."


except ValueError as ex:
    print(ex)


else:
    print(s)

Answer 1

Ask for forgiveness - 将输入的值转换为float 并处理ValueError:

try:
    s = float(input("Enter a numerical value: "))
except ValueError:
    print("Non numberrical value...")
else:
    print(getSqrt(s))

演示:

>>> try:
...     s = float(input("Enter a numerical value: "))
... except ValueError:
...     print("Non numberrical value...")
... 
Enter a numerical value: s4
Non numberrical value...