这个 try-except 子句如何识别整数？

Question

我是编程新手，我试图了解 Python 如何解释命令，在这种情况下，我无法理解 Python 如何知道使用 try-except 子句识别整数、浮点数或字符串。这是我的代码（请原谅厚脸皮）

print("DETECTING INPUT TYPE WITH LIMITED CHANCES")
print("Enter an integer and ONLY AN INTEGER. YOU HAVE ONLY 5 CHANCES")
n=0
final=0
for n in range(5):
    abc=input()
    try:
        int(abc) #This line checks for whether the input is an integer. If this is a floating number, the int() operator executes and
        # converts the number to an integer
        final=1
        break
    except:
        try:
            float(abc)
            print("WHAT DID I TELL YOU? YOU PUT IN A FLOATING NUMBER! DO IT RIGHT!")
            print("Enter an integer and ONLY AN INTEGER")
        except:
            print("...you put a string didn't you? HOW DARE YOU DEFY THIS PROGRAM? DO IT RIGHT!")
            print("Enter an integer and ONLY AN INTEGER")
if final==1:
    print("Good... very good, here is your number:",abc)
else:
    print("You were given 5 chances and you couldn't get it right.")

此代码按预期工作，但是当我放入一个浮点数时，程序如何抛出异常以允许 try-except 子句执行？例如，当我在执行程序时输入“1.0”时会发生以下情况：

DETECTING INPUT TYPE WITH LIMITED CHANCES
Enter an integer and ONLY AN INTEGER. YOU HAVE ONLY 5 CHANCES

1.0
WHAT DID I TELL YOU? YOU PUT IN A FLOATING NUMBER! DO IT RIGHT!
Enter an integer and ONLY AN INTEGER

然后我纠正自己并输入一个整数时的样子：

1
Good... very good, here is your number: 1

但是，如果我在控制台中手动输入以下内容，我不会收到错误消息。相反，int() 命令执行它应该做的事情，并将我的浮点数转换为整数。

abc=1.0

int(abc)
Out[3]: 1

try-except 子句对 int() 运算符做了什么以引发异常并允许我的代码正确执行？

谢谢！

Answer 1

input 的结果是一个字符串。要在控制台中复制它，您应该这样做

abc = "1.0"

然后int(abc) 将按预期引发 ValueError。