Re: [PHP] variable type - conversion/checking

On 16-3-2013 19:20, Matijn Woudt wrote:
> On Sat, Mar 16, 2013 at 6:52 PM, Maciek Sokolewicz <
> [email protected]> wrote:
>
>> Hi,
>>>
>>> I have tried to find a way to check if a character string is possible to
>>> test whether it is convertible to an intger !
>>>
>>> any suggestion ?
>>>
>>> BR georg
>>>
>>
>> All responses in this thread have been very nice; but you could also try a
>> much simpler 2-step check:
>>
>> 1. is_numeric
>> 2. if true > check if there's a decimal character in the string:
>>
>> if(is_numeric($str) && false === strpos('.', $str)) {
>>     // it's an int for sure
>> } else {
>>     // might be a number, but it's definitly not an int
>>
>> }
>>
>
> Wrong.  is_numeric will accept 1e1, which is a float, so you would need to
> check for e or E too.
>
> - Matijn
>
Although in theory I agree, indeed any e* number is treated as a 
floating point number. However, considering the exponent and the base 
are forced to be integer numbers (due to exclusion of decimal points), 
in the real number system, you will *always* end up with a natural 
number, i.e. integer. Regardless of your input.

So as a result, the input could always be interpreted as an integer, 
without any precision-loss using the method above.
- Tul