PHP Special Types PHP

There are 2 special data types in PHP

1. Resource
2. Null

Resource Data type:

It refers the external resources like database connection, FTP connection, file pointers, etc. In simple terms, a resource is a special variable which carrying a reference to an external resource.

Example 1

1. <?php  
2.     $conn = ftp_connect("127.0.0.1") or die("Could not connect");  
3.     echo get_resource_type($conn);  
4. ?>  

Example 2

1. <?php  
2.     $conn= ftp_connect("127.0.0.1") or die("could not connect");  
3.     echo $conn;  
4. ?>  

Example 3

1. <?php  
2.     $handle = fopen("tpoint.txt", "r");  
3.     var_dump($handle);  
4.     echo "<br>";  
5.     $conn= ftp_connect("127.0.0.1") or die("could not connect");  
6.     var_dump($conn);  
7. ?>  

Null Data Type:

A variable of type Null is a variable without any data. In PHP, null is not a value, and we can consider it as a null variable based on 3 condition.

1. If the variable is not set with any value.
2. If the variable is set with a null value.
3. If the value of the variable is unset.

Example 1

1. <?php  
2.        
3.     $empty=null;  
4. var_dump($empty);  
5. ?>  

Example 2

1. <?php  
2.         $a1 = " ";  
3.      var_dump($a1);  
4.         echo "<br />";  
5.         $a2 = null;  
6.         var_dump($a2);  
7. ?>  

Example 3

1. <?php  
2.     $x = NULL;  
3.     var_dump($x);  
4.     echo "<br>";  
5.     $y = "Hello javatpoint!";  
6.     $y = NULL;  
7.     var_dump($y);  
8. ?>