PHP is loosely typed, which means it calculates data types as data is assigned to each variable.

Type	Description
Integer	A whole number
Double	A floating-point number
String	A collection of characters Boolean Array One of the special values true or false.
Array	Arrays are named and indexed collections of other values.
Objects	Objects are instances of programmer-defined classes,which can kinds of values and functions that are specific to the class.

Special Data Types

Type	Description
Resource	Reference to a third-party resource (e.g - a database)
Null	An uninitialized Variable.

• Constants have global scope, so they are accessible.


• After they have been defined ,We can use everywhere in your scripts as well as inside functions.

Example :

<?php
define("Greeting","TechKnow Heights"); 
echo constant("Greeting "); 
?>

• Echo : The simplest use of echo is to print a string as argument.

Example :

echo "it is example to print a string .";
Or
echo("it is example to print the string .");



• Print :Print can accept only one argument and returns a value, which represents whether the print statement succeeded.