在 Python 中使用 try/except 将字符串转换为 Int

Question

所以我很困惑如何使用 try/except 函数将字符串转换为 int。有谁知道如何做到这一点的简单功能？我觉得我在字符串和整数上仍然有点朦胧。我非常有信心整数与数字有关。字符串...不是那么多。

Answer 1

在使用 try/except 块时，请务必具体说明您要捕获的异常。

string = "abcd"
try:
    string_int = int(string)
    print(string_int)
except ValueError:
    # Handle the exception
    print('Please enter an integer')

Try/Excepts 非常强大，因为如果某事可能以多种不同的方式失败，您可以指定您希望程序在每种失败情况下如何反应。

Answer 2

这里是：

s = "123"
try:
  i = int(s)
except ValueError as verr:
  pass # do job to handle: s does not contain anything convertible to int
except Exception as ex:
  pass # do job to handle: Exception occurred while converting to int

Answer 3

首先，try / except 不是函数，而是语句。

要在 Python 中将字符串 (or any other type that can be converted) 转换为整数，只需调用 int() 内置函数即可。 int() 将 raise 一个 ValueError 如果它失败了，你应该特别抓住这个：

在 Python 2 中。x：

>>> for value in '12345', 67890, 3.14, 42L, 0b010101, 0xFE, 'Not convertible':
...     try:
...         print '%s as an int is %d' % (str(value), int(value))
...     except ValueError as ex:
...         print '"%s" cannot be converted to an int: %s' % (value, ex)
...
12345 as an int is 12345
67890 as an int is 67890
3.14 as an int is 3
42 as an int is 42
21 as an int is 21
254 as an int is 254
"Not convertible" cannot be converted to an int: invalid literal for int() with base 10: 'Not convertible'

在 Python 3 中。x

语法略有变化：

>>> for value in '12345', 67890, 3.14, 42, 0b010101, 0xFE, 'Not convertible':
...     try:
...         print('%s as an int is %d' % (str(value), int(value)))
...     except ValueError as ex:
...         print('"%s" cannot be converted to an int: %s' % (value, ex))
...
12345 as an int is 12345
67890 as an int is 67890
3.14 as an int is 3
42 as an int is 42
21 as an int is 21
254 as an int is 254
"Not convertible" cannot be converted to an int: invalid literal for int() with base 10: 'Not convertible'

Answer 4

在很多情况下，我们希望从用户那里得到一个整数值。用户可能会插入应该被警告的非整数值，并且应该提示他们重试。下面的 sn-p 可用于从用户那里获取一个整数值，并继续提示用户插入一个整数，直到他们输入一个有效的整数。

def get_integer_value():
  user_value = input("Enter an integer: ")
  try:
    return int(user_value)
  except ValueError:
    print(f"{user_value} is not a valid integer. Please try again.")
    return get_integer_value()


if __name__ == "__main__":
  print(f"You have inserted: {get_integer_value()}")
    

输出：

Enter an integer: asd
asd is not a valid integer. Please try again.
Enter an integer: 32
You have inserted: 32

Answer 5

你可以这样做：

try : 
   string_integer = int(string)
except ValueError  :
   print("This string doesn't contain an integer")