difference between if($value) and if(isset($value))

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corecoder
Forum Newbie
Posts: 6
Joined: Fri Aug 14, 2009 3:57 am

difference between if($value) and if(isset($value))

Post by corecoder »

Hi all,

what is the difference between difference between if($value) and if(isset($value)). both returns true is value is exists. which the best one to use ?
Mark Baker
Forum Regular
Posts: 710
Joined: Thu Oct 30, 2008 6:24 pm

Re: difference between if($value) and if(isset($value))

Post by Mark Baker »

corecoder wrote:what is the difference between difference between if($value) and if(isset($value)). both returns true is value is exists. which the best one to use ?
Try

Code: Select all

 
echo '<b>Test 1, $value not set</b>';
echo '<br />';
if($value) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
if(isset($value)) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
 
$value = 9;
echo '<b>Test 2, $value is numeric 9</b>';
echo '<br />';
if($value) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
if(isset($value)) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
 
$value = 0;
echo '<b>Test 3, $value is numeric 0</b>';
echo '<br />';
if($value) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
if(isset($value)) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
 
$value = False;
echo '<b>Test 4, $value is boolean false</b>';
echo '<br />';
if($value) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
if(isset($value)) { echo '$value is true'; } else {echo '$value is false'; }
 
and see what the differences are
User avatar
jazz090
Forum Contributor
Posts: 176
Joined: Sun Apr 12, 2009 3:29 pm
Location: England

Re: difference between if($value) and if(isset($value))

Post by jazz090 »

if(value) checks if value is (bool) TRUE whilst isset does what its supposed to. always use the latter for checking if a var is declared.
corecoder
Forum Newbie
Posts: 6
Joined: Fri Aug 14, 2009 3:57 am

Re: difference between if($value) and if(isset($value))

Post by corecoder »

Mark Baker wrote:
corecoder wrote:what is the difference between difference between if($value) and if(isset($value)). both returns true is value is exists. which the best one to use ?
Try

Code: Select all

 
echo '<b>Test 1, $value not set</b>';
echo '<br />';
if($value) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
if(isset($value)) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
 
$value = 9;
echo '<b>Test 2, $value is numeric 9</b>';
echo '<br />';
if($value) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
if(isset($value)) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
 
$value = 0;
echo '<b>Test 3, $value is numeric 0</b>';
echo '<br />';
if($value) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
if(isset($value)) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
 
$value = False;
echo '<b>Test 4, $value is boolean false</b>';
echo '<br />';
if($value) { echo '$value is true'; } else {echo '$value is false'; }
echo '<br />';
if(isset($value)) { echo '$value is true'; } else {echo '$value is false'; }
 
and see what the differences are
thanks buddy
any idea about this question viewtopic.php?f=1&t=104684
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