On Nov 27, 2008, at 12:55 PM, Jason Grout wrote:
> mabshoff wrote:
>>
>>
>> On Nov 27, 12:34 pm, "William Stein" <[EMAIL PROTECTED]> wrote:
>>> On Thu, Nov 27, 2008 at 12:30 PM, mabshoff
>>> <[EMAIL PROTECTED]> wrote:
>>>
>>>> On Nov 27, 11:24 am, Jason Grout <[EMAIL PROTECTED]>
>>>> wrote:
>>>>> Ronan Paixão wrote:
>>>>>> I just found a problem with Integer(). It doesn't seem to work
>>>>>> fine with
>>>>>> float strings.
>>>>>> Those work fine:
>>>>>> Integer("1")
>>>>>> Integer(1.)
>>>>>> But this doesn't:
>>>>>> Integer("1.")
>>>>> More data:
>>>>> Integer(RR('1.')) works
>>>>> Integer(RR('1.0')) works
>>>>> Integer('1.0') doesn't work
>>>>> I think that at least '1.' ought to be converted to an integer.
>>>> Seems like a reasonable request. I would even allow ("$FOO.0").
>>>> Care
>>>> to open a ticket?
>>> I strongly disagree, since pure Python does not allow this, and
>>> Sage's string conversion of integers should be consistent with that:
>>
>> Ok, that is certainly a killer argument against this.
>>
>> <SNIP>
>>
>> But how about some functions that do convert "1.0" and "1." to an
>> Integer object? I have no good suggestion how to name there or where
>> to stick them, but it seems that they could come in useful. One could
>> always use regular expressions to transform the string since this is
>> all about getting pexepct output from Scilab to play nice with Sage.
I think Integer(float(1)) should work, but Integer(float(1.5)) should
throw an error (NOT truncate like int does). Also, I am against
Integer("1.0") raising an error, it even does for Python's int.
> Since {RR,QQ}->Integer *does* work, you could do:
>
> Integer(sage_eval('1.'))
>
> Integer(sage_eval('2/2'))
>
> Integer(sage_eval('1.0'))
>
> or something like:
>
> try:
> return Integer(RR(my_string))
> except TypeError:
> return Integer(QQ(my_string))
>
>
> Of course, using sage_eval for this is a bit like using a sledgehammer
> to hammer a nail.
Not to mention a potential security risk, e.g. if you're "reading in"
the Integer "os.system('723...938 * rm -rf /')" you got in a file
from somewhere.
- Robert
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