Description

Booleans are the easiest type. It can be either TRUE or FALSE. It is used in control structure like the testing portion of an if statement.

Consider the following example :

<?php
$height=100;
$width=50;
if ($width == 0)
{
echo "The width needs to be a non-zero number";
}
?>

In the above code the result of the equal-than operator is a Boolean. In this case, it would be false and, therefore, the echo statement will never execute.

Now consider the next example :

<?php 
$height=100;
$width=50;
if ($width) 
{ 
echo "The area of the rectangle is".$height*$width; 
}
else 
{ 
echo "The width needs to be a non-zero number";
}
?>

In this example no comparison operator is used. But PHP automatically converted $width value 50 to its Boolean equivalent true and calculate the area of the rectangle i.e. execute the commands inside the if() statement.

List of the types of Boolean values equivalents

Data Type	True Value	False value
Integer	All non-zero values	0
Floating point	All non-zero values	0.0
Strings	All other strings	Empty strings ()"" The zero string ()"0"
Null	Never	Always
Array	If it contains at least one element	If it does not contain any elements
Object	Always	Never
Resource	Always	Never



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