Data Types

 
Data Types:-

Booleans
Description

Booleans is 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 value 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

 

Integers and Floating point numbers

Strings

Arrays

Objects

NULL

 

“source: http://www.w3resource.com/php/data-types/booleans.php”