[RESOLVED] Difference between if($var) and if(isset($var))?

[JLHeidecker]

What is the difference between if($var) and if(isset($var))?

thanks!
J

[devinemke]

if($var) will evaluate true if $var is considered BOOLEAN true

if(isset($var)) will evaluate true if $var is set

[JLHeidecker]

Then how come the following runs without error?

<?php

$var = 4;
if($var)
{$Return = 'true';}
else
{$Return = 'false';}

echo $Return; // output is 'true'

?>

If $var is not type boolean, does php then try to evaluate an isset($var)?

[devinemke]

there is no error because that code is perfectly valid. 4 is an inetger that is not 0 thus it is evulated as TRUE. look at this table to see how various types are evaluated.

[JLHeidecker]

thanks! that table is something I had not seen before.