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。有没有我没找到的？

Answer 1

最简单的方法就是尝试将其变成浮点数。

try:
    float(str)
except ValueError:
    # not float
else:
    # is float

Answer 2

我建议使用 try except 子句的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 3

正如 Macattack and Jab, you could use try except, which you can read about in python's docs or w3school's tutorial 所述。

Try Except 子句的形式为：

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

有关 built-in 例外情况的列表，请参阅 python's docs。

是否有内置方法来检查字符串是否可以转换为浮点数？

Is there built-in way to check if string can be converted to float?

python

string

double

type-conversion