Learn About PHP Variables

In this blog you will learn about PHP Variables.

Introduction 

 

In my previous blog, I talked about a basic introduction to PHP.

 

In this blog, we will discuss "PHP VARIABLES".

 

PHP Variables

 

What is Variable?

• Variables are used to store the value and access the stored value in the program.

In PHP, variables begin with the "$" symbol, followed by the Variable name.

 

Example:

<?php
  $a = 2;
?>

Rules for assigning a Variables:

 

Basically, a Variable can have a short name (like i,e., x,y,etc..) or larger names (like i,e., first,age_group,etc..),

• A Variable name must start with underscore characters or with a letter.
• A Variable name cannot begin with numbers.
• A variable name can contain only alpha-numeric characters and underscores ( A-Z, 0-9 and _ ).
• Variable names are case-senstive($NAME, $name), these names are two different variable names.

PHP OUTPUT VARIABLES

• The "echo" statement is often used to show the output to the screen.

Example 1

<?php
   $m = "BEST WISHES!";
   echo"$m";
?>

Example 2

<?php
    $a = 2;
    $b = 1;
    echo $a + $b ;
 ?>

PHP VARIABLES SCOPE

• Variables are declared anywhere in the program script.
• A PHP consist of three types of variable scopes:

1. Global
2. Local
3. Static

Global Variable

• A variable declared outside of the function is known as a global variable.
• It can be accessed outside of the function and anywhere in the program.

Example 1

<?php
   $x = 2; // global variable
   function test()
   {
      echo"<p>WELCOME: $x</p>";
   }
   test();
   echo"<p>WELCOME : $x</p>"
?>

• The global variables are accessed from inside of the function with the help of the keyword "global".
• Use the "global" keyword before the declared function variable (inside).

Example 2

<?php
   $a = 2;
   $b = 2;
   function test()
   {
      global $a, $b; // global keyword is used
      $b = $a * $b;
   }
   test();
   echo $b ;
?>

Local Variable

• A variable declared inside of the function is known as local variable.
• It can be accessed only inside that function.
• The local variables can have the same names with different functions because they can be recognized only by their declared function names.

Example:

<?php
   function test()
   {
      $x = 2; // local variable
      echo"<p>WELCOME: $x</p>";
   }
   test();
   echo"<p>WELCOME FUNCTION IS : $x</p>";
?>

Static Variable

• Generally,when the function gets executed,all the variables in the function are deleted.
• Sometimes, we want some of the local variables for further references.
• For that purpose, use the "static" keyword before the variable in the function declaration.

Example

<?php
   function test2()
   {
      static $a = 1; // static variable
      echo"$a";
   }
   test2();
?>

These are all the PHP Variables.

 

Here, I have attached the example codings for the above-discussed topics. Kindly refer to it.

 

Thank you!.