php-general Digest 22 Jun 2012 21:07:28 -0000 Issue 7864
Topics (messages 318285 through 318288):
Re: why is (intval('444-44444') == '444-44444') EQUAL??!
318285 by: Robert Cummings
318286 by: Mike Mackintosh
318287 by: marco.behnke.biz
If PHP Were British
318288 by: Daevid Vincent
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On 12-06-21 10:27 PM, Daevid Vincent wrote:
Huh? Why is this equal??!
php> $id = '444-44444';
php> var_dump($id, intval($id));
string(9) "444-44444"
int(444)
php> if (intval($id) == $id) echo 'equal'; else echo 'not equal';
equal
or in other words:
php> if (intval('444-44444') == '444-44444') echo 'equal'; else
echo 'not equal';
equal
I would expect PHP to be evaluating string "444-44444" against integer "444"
(or string either way)
however, just for giggles, using === works...
php> if ($id === intval($id)) echo 'equal'; else echo 'not equal';
not equal
Using === will always fail because on the left you have a string and on
the right you have an integer which fails exact comparison based on
datatype mismatch.
When comparing a string to an integer using == PHP performs type
juggling and converts the string to an integer first.
Cheers,
Rob.
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--- Begin Message ---
Using == will compare the two values after type juggling is performed. === will
compare based on value and type (identical).
PHP Will type juggle the string to an integer.
Your if/else is just like saying:
php> if (444 == "444") echo 'equal'; else echo 'not equal';
equal
--
Mike Mackintosh
PHP 5.3 ZCE
On Thursday, June 21, 2012 at 10:27 PM, Daevid Vincent wrote:
> Huh? Why is this equal??!
>
> php > $id = '444-44444';
>
> php > var_dump($id, intval($id));
> string(9) "444-44444"
> int(444)
>
> php > if (intval($id) == $id) echo 'equal'; else echo 'not equal';
> equal
>
> or in other words:
>
> php > if (intval('444-44444') == '444-44444') echo 'equal'; else
> echo 'not equal';
> equal
>
> I would expect PHP to be evaluating string "444-44444" against integer "444"
> (or string either way)
>
> however, just for giggles, using === works...
>
> php > if ($id === intval($id)) echo 'equal'; else echo 'not equal';
> not equal
>
>
> --
> PHP General Mailing List (http://www.php.net/)
> To unsubscribe, visit: http://www.php.net/unsub.php
>
>
--- End Message ---
--- Begin Message ---
Daevid Vincent <dae...@daevid.com> hat am 22. Juni 2012 um 04:27 geschrieben:
> Huh? Why is this equal??!
http://de2.php.net/manual/en/language.types.type-juggling.php
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--- Begin Message ---
http://www.addedbytes.com/blog/if-php-were-british/
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