这个 try-except 子句如何识别整数?

Question

我是编程新手，我试图理解Python如何解释命令，在这种情况下，我很难理解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.")

这段代码按预期工作，但是当我输入浮点数时，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，会发生什么情况：

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

然后当我纠正自己并输入一个整数时它是什么样子：

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

但是，如果我在控制台中手动键入以下内容，则不会收到错误。相反，int(( 命令会执行它应该执行的操作，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)将按预期引发一个 ValueError。