assigning variables to null

helz

if i do:
$var = NULL

are these if statements the same?

if($var)
//var is not null

if($var != NULL)
//var is not null

Shrike

yes but only because PHP will automatically convert types 'on-the-fly'. Consider

$var = 0;
$var2 = "0";
if ( $var == $var2 )
{
  echo "Yes";
}
// You can force an actual type check using the === operator
if( $var === $var2 )
{
  echo "Yes";
}

helz

oh
so it will convert = "0" to = 0 straight away.
whats the === operator?

also i changed it to $var = FALSE
and then did if($var)

Shrike

That would still evaluate to true, since if ( $var ) just checks whether $var is a set variable.
Try:

error_reporting(E_ALL);
if ( $var  ) 
{ 
  echo "Yes"; 
}

The === operator is for checking variable type.

helz

what would you suggest?
scenario:
function CustomFunc ($var, $var2 = NULL, $var3 = FALSE, $var4 = 0)

ive always thought that an if statement checks whether the statement is true, so if the variable is set to false why does it only check whether it is set?

Shrike

Sorry my bad. You are right, a false variable would cause the if to fail.