是否有内置方法来检查字符串是否可以转换为浮点数？

Question

我知道有一些方法可以检查 str 是否可以使用 try- except 或正则表达式进行转换，但我一直在寻找（例如） str 方法，例如str.isnumeric()str.isdigit()str.isdecimal() # also doesn't work for floats但找不到任何。还有我还没找到的吗？

Answer 1

我建议使用 try except 子句请求宽恕而不是许可方法：

str_a = 'foo'

str_b = '1.2'

def make_float(s):

    try:

        return float(s)

    except ValueError:

        return f'Can't make float of "{s}"'

>>> make_float(str_a)

Can't make float of "foo"

>>> make_float(str_b)

1.2

Answer 2

Try except 子句的形式如下：

try:

    # write your code

    pass

except Exception as e: # which can be ValueError, or other's exceptions

    # deal with Exception, and it can be called using the variable e

    print(f"Exception was {e}") # python >= 3.7

    pass

except Exception as e: # for dealing with other Exception

    pass

# ... as many exceptions you would need to handle

finally:

    # do something after dealing with the Exception

    pass

Answer 3

最简单的方法就是尝试将其变成浮动。

try:

    float(str)

except ValueError:

    # not float

else:

    # is float