Re: distinguish between null variable and unset variable

From:	Carlos Medina	Date:	Thu, 22 Jan 2009 22:07:09 +0000
Subject:	Re: distinguish between null variable and unset variable
References:	1 2 3 4 5 6 7	Groups:	php.general
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Shawn McKenzie schrieb:

Daniel Brown wrote:
On Thu, Jan 22, 2009 at 15:12, Daniel Brown <danbrown@php.net> wrote:
Unfortunately, neither solution would work. isset() will return FALSE even for an instantiated and explicitly-defined NULL variable.
    Forgot to mention that, in addition, is_null() will return TRUE
for both explicitly-set NULL variables and undefined variables alike.
That's why I was testing isset() fist, however as you pointed out, that is crap also. :-(

$testvariable1; $testvariable2 = null; $testvariable3 = ''; var_dump($testvariable1); var_dump($testvariable2); var_dump($testvariable3); var_dump( isset( $testvariable1)); var_dump( isset( $testvariable2)); var_dump( isset( $testvariable3)); var_dump( is_null( $testvariable1)); var_dump( is_null( $testvariable2)); var_dump( is_null( $testvariable3)); NULL NULL string(0) "" bool(false) bool(false) bool(true) bool(true) bool(true) bool(false) Regards Carlos