Question

我在Python 3.x中编写了以下代码来验证用户的输入：

while True:
    try:
        answer = int(input("Enter an integer: "))
    except ValueError:
        print("That's not a whole number. Try again.")

我知道输入'hi'或'hi46'会是字符串（会导致ValueError）。

输入什么数据类型''（什么都没有）？输入']％$'（符号）怎么样？

Answer 1

假设您正在使用python 3.X，所有，用户输入将是一个字符串。甚至数字看上去像“23”或“0”。 int(thing)不验证thing是否为整数类型。它试图将thing从现在的任何类型转换为整数类型，如果不可能则引发ValueError。

演示：

>>> while True:
...     x = input("Enter something: ")
...     print("You entered {}".format(x))
...     print("That object's type is: {}".format(type(x)))
...
Enter something: hi
You entered hi
That object's type is: <class 'str'>
Enter something: hi46
You entered hi46
That object's type is: <class 'str'>
Enter something: 
You entered
That object's type is: <class 'str'>
Enter something: ]%$
You entered ]%$
That object's type is: <class 'str'>
Enter something: 23
You entered 23
That object's type is: <class 'str'>
Enter something: 42
You entered 42
That object's type is: <class 'str'>
Enter something: 0
You entered 0
That object's type is: <class 'str'>

Answer 2

字符串，您input()的所有内容都是字符串。除了C-c int()如果Query query = pm.newQuery(Register.class); query.setFilter("email== eemail"); query.declareParameters("string eemail"); return (Member)query.execute(email);提出它，所有这些都会引起价值误差。

Answer 3

您可以在不依赖于使用isdigit（）的情况下执行此操作：

answer = input("Enter an integer: ")
while not answer.isdigit():
    print("That's not a whole number. Try again.")
    answer = input("Enter an integer: ")
answer = int(answer)

isdigit（）测试输入字符串是否完全由可以用int（）转换的数字组成。

Python - 用户输入数据类型

3 个答案: