A question about string and float number

Timothy Grant timothy.grant at gmail.com
Fri Aug 8 00:15:33 CEST 2008


That's because s IS a string. It's not been converted to a float.

In [1]: s = '3.1415'
In [2]: n = float(s)
In [3]: type(s)
Out[3]: <type 'str'>
In [4]: type(n)
Out[4]: <type 'float'>

Why are you avoiding the very simple try:/except: solution to this problem?

On Thu, Aug 7, 2008 at 1:28 PM, Wei Guo <weiguo6 at gmail.com> wrote:
> Hi I tried the first type method but it seens that it doesn't work. Could
> anyone help me about it?
>
>>>> s = '3.145'
>>>> type(s) == type(float())
> False
>>>> type(s)
> <type 'str'>
>>>> type(float())
> <type 'float'>
>>>>
>
> Best regards,
>
> Wei
>
>
> On 8/7/08, Wei Guo <weiguo6 at gmail.com> wrote:
>>
>> Hi Thanks for Tyler and Edwin's help.
>>
>> For my questions, I need to import some xml file and there are floating
>> number and strings in it. I need to process string and number differently.
>> This is reason that I am asking question here. Is this background
>> information we need for this quesions.
>>
>> Btw, which way is better? type or with exception ValueError?
>>
>> Thanks,
>>
>> Wei
>>
>>
>> On 8/6/08, Tyler Breisacher <dancinguy at linkline.com> wrote:
>>>
>>> It's generally a bad idea to use "except" without naming a specific
>>> exception. The exception you might expect in this case is ValueError. Any
>>> other exception *should* be uncaught if it happens. By the way, this method
>>> will return true for integers as well as floats. For example, isFloat('3')
>>> will return 3.0. So make sure this is what you want, since it wasn't 100%
>>> clear from the original message.
>>>
>>>
>>> Wei Guo wrote:
>>>>
>>>> #this is a better way of testing a string for float
>>>> def isFloat(s):
>>>>    try:
>>>>        s = float(s)
>>>>    except:
>>>>        return False
>>>>    return True
>>>
>>>
>>> --
>>> http://mail.python.org/mailman/listinfo/python-list
>>
>
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>



-- 
Stand Fast,
tjg.  [Timothy Grant]



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