Re: [PHP] variable type - conversion/checking

2013/3/16 Ashley Sheridan <[email protected]>

>
>
> tamouse mailing lists <[email protected]> wrote:
>
> >On Fri, Mar 15, 2013 at 4:00 PM, Ashley Sheridan
> ><[email protected]>wrote:
> >
> >> **
> >> On Fri, 2013-03-15 at 04:57 -0500, tamouse mailing lists wrote:
> >>
> >> On Fri, Mar 15, 2013 at 3:55 AM, Peter Ford <[email protected]>
> >wrote:
> >> > On 15/03/13 06:21, Jim Lucas wrote:
> >> >>
> >> >> On 3/14/2013 4:05 PM, Matijn Woudt wrote:
> >> >>>
> >> >>> On Thu, Mar 14, 2013 at 11:44 PM, Jim Lucas <[email protected]>
> >wrote:
> >> >>>
> >> >>>> On 03/14/2013 11:50 AM, Samuel Lopes Grigolato wrote:
> >> >>>>
> >> >>>>> Something like "if (is_numeric($var)&& $var == floor($var))"
> >will do
> >> >>>>> the
> >> >>>>>
> >> >>>>> trick. I don't know if there's a better (more elegant) way.
> >> >>>>>
> >> >>>>>
> >> >>>>> On Thu, Mar 14, 2013 at 3:09 PM, Matijn
> >Woudt<[email protected]> wrote:
> >> >>>>>
> >> >>>>> On Thu, Mar 14, 2013 at 7:02 PM,
> >georg<[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
> >> >>>>>>>
> >> >>>>>>
> >> >>>>>>
> >> >>>>>> You could use is_numeric for that, though it also accepts
> >floats.
> >> >>>>>>
> >> >>>>>> - Matijn
> >> >>>>>>
> >> >>>>>>
> >> >>>>>
> >> >>>> for that type of test I have always used this:
> >> >>>>
> >> >>>> if ( $val == (int)$val ) {
> >> >>>>
> >> >>>> http://www.php.net/manual/en/**language.types.integer.php#**
> >> >>>>
> >> >>>>
> >language.types.integer.casting<
> http://www.php.net/manual/en/language.types.integer.php#language.types.integer.casting
> >
> >> >>>>
> >> >>>>
> >> >>>>
> >> >>> I hope you're not serious about this...
> >> >>>
> >> >>> When comparing a string and an int, PHP will translate the string
> >to int
> >> >>> too, and of course they will always be equal then.
> >> >>> So:
> >> >>> $a = "abc";
> >> >>> if($a == (int)$a) echo "YES";
> >> >>> else echo "NO";
> >> >>> Will always return YES.
> >> >>>
> >> >>> - Matijn
> >> >>>
> >> >>
> >> >> Hmmmm... Interesting. Looking back at my code base where I thought
> >I was
> >> >> doing that, turns out the final results were not that, but this:
> >> >>
> >> >> $value = "asdf1234";
> >> >>
> >> >> if ( $value === (string)intval($value) ) {
> >> >>
> >> >> Looking back at the OP's request and after a little further
> >searching,
> >> >> it seems that there might be a better possible solution for what
> >the OP
> >> >> is requesting.
> >> >>
> >> >> <?php
> >> >>
> >> >> $values = array("asdf1234", "123.123", "123");
> >> >>
> >> >> foreach ( $values AS $value ) {
> >> >>
> >> >> echo $value;
> >> >>
> >> >> if ( ctype_digit($value) ) {
> >> >> echo ' - is all digits';
> >> >> } else {
> >> >> echo ' - is NOT all digits';
> >> >> }
> >> >> echo '<br />'.PHP_EOL;
> >> >> }
> >> >>
> >> >> returns...
> >> >>
> >> >> asdf1234 - is NOT all digits
> >> >> 123.123 - is NOT all digits
> >> >> 123 - is all digits
> >> >>
> >> >> http://www.php.net/manual/en/function.ctype-digit.php
> >> >>
> >> >> An important note:
> >> >>
> >> >> This function expects a string to be useful, so for example
> >passing in
> >> >> an integer may not return the expected result. However, also note
> >that
> >> >> HTML forms will result in numeric strings and not integers. See
> >also the
> >> >> types section of the manual.
> >> >>
> >> >> --
> >> >> Jim
> >> >>
> >> >
> >> > Integers can be negative too: I suspect your test would reject a
> >leading
> >> > '-'...
> >>
> >>
> >> For my money, `is_numeric()` does just what I want.
> >>
> >>
> >>
> >> The thing is, is_numeric() will not check if a string is a valid int,
> >but
> >> any valid number, including a float.
> >>
> >> For something like this, wouldn't a regex be better?
> >>
> >> if(preg_match('/^\-?\d+$/', $string))
> >>     echo int
> >>
> >>   Thanks,
> >> Ash
> >> http://www.ashleysheridan.co.uk
> >>
> >>
> >>
> >That is so about is_numeric(), but once I know it's a numeric, coercing
> >it
> >to just an int is easy. *Validating*, rather than just assuring, that a
> >string is an integer is another matter; if you need to give feedback to
> >the
> >user, etc., in which case a Regex is better.
> >
> >(One small nit, + is possible on integers, too.)
>
> The op wasn't about casting a string to an int but detecting if a string
> was just a string representation of an int. Hence using a regex to
> determine that. Regular expressions are not just about giving feedback to
> the user.
>

Guess regex are the only useful solution here. When you consider to use
built-in functions, just remember, that for example '0xAF' is an integer
too, but '42.00' isn't.


>
> Thanks,
> Ash
> http://www.ashleysheridan.co.uk
>
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