更清晰的代码来解决在 Python 中打印 Int 值

Question

我有一段代码要求用户年龄。用户的输入类型为int。此外，如果用户不想输入任何内容，他们可以按 'Enter' 退出程序（如下）：

print("What is your age?")
answer = int(input())
if answer == '':
    print("Don't want to disclose? That's fine.")

但是，当我按下 Enter 时，出现以下错误：

Traceback (most recent call last):
  File "C:/Users/test/PycharmProjects/exceptions/testinput.py", line 2, in <module>
    answer = int(input())
ValueError: invalid literal for int() with base 10: ''

Process finished with exit code 1

我知道我可以做一个 try 块并且代码像我想要的那样工作：

print("What is your age?")
try:
    answer = int(input())
    if answer == '':
        print()
except ValueError:
        print("Don't want to disclose? That's fine.")

我的问题是，除了 try 块之外，还有其他方法可以打印 int 类型的空白值吗？

Answer 1

当然：在转换为 int:

之前检查输入
answer = input("What is your age? ") if answer == '': print("Don't want to disclose? That's fine.") else: ...

Answer 2

我会从 int 函数中删除 input 调用。

print("What is your age?")
answer = input()
answer = int(answer) if answer else None
if not answer: print("Don't want to disclose? That's fine.")

Answer 3

另一种方法是三思而后行，使用if-else并在需要时在else内进行int转换：

answer = input("What is your age?")

if answer == "":
    print("Don't want to disclose? That's fine.")
else:
    answer = int(answer)

但是现在你需要考虑 answer 是否是构成字符串的有效整数，例如如果用户输入 foobar 怎么办？（提示： 现在您还需要使用 str.isdecimal 或类似方法进行检查）。

Answer 4

输入函数将输入转换为String，如doc

中所述

input([prompt]) If the prompt argument is present, it is written to standard output without a trailing newline. The function then reads a line from input, converts it to a string (stripping a trailing newline), and returns that. When EOF is read, EOFError is raised.

因此，当您什么都不输入时，您正在尝试将 int 类型转换为字符串 ('')，类似于 int('xyz')，因此得到值错误异常

ValueError: invalid literal for int() with base 10: 'xyz'

如果数字包含在 String 类型中，例如int('2')，其类型转换良好。

您或许可以这样来代替：

print("What is your age?")
answer = input()
if answer == '':
    print("Don't want to disclose? That's fine.")
else:
    int(answer)

更清晰的代码来解决在 Python 中打印 Int 值

Cleaner code to get around Printing an Int value in Python

python

printing

int