PHP Variable Declaration, Naming Conventions, Data Types

How to Create PHP Variables

हिन्दी | PHP Variables


What is Variable in PHP

PHP Variables are containers which are used to store data or information.


PHP Variable Declaration

In PHP All variable names must start with a $ sign, followed by the name of the variable. Like this$variable_name

You can declare variables anywhere in the PHP script.


Assign Value to a Variable

Use the = equal sign to assign value for a variable. Like this – $name = "John Doe";

This = equal sign is called Assignment Operator.

<?php
  $name = "John Doe"; // Declaring a variable
  echo $name; // Displaying the variable value
?>
Browser Output
John Doe

Naming Conventions of a Variable

To Declare or Create a PHP Variable you need to follow some Rules –

  1. Variable Must start with a $ sign.
  2. Variable name must start with a letter or the _ underscore character.
  3. A variable name cannot start with a number.
  4. A variable name can only contain alpha-numeric characters and underscores (A to z, 0 to 9 and _ )

In PHP, variable names are case-sensitive. In the below example both are different variables –

$searchengine = "Google";
$searchEngine = "Yahoo";

PHP Data Types

PHP Data Types

हिन्दी | PHP Data Types

You can assign all the data types in a variable, that are available in PHP.

Below, the list of the PHP Data Types with a short description –

1 – String – A string is a sequence of characters, that are inside a single or double quote.

$x = "Hello world";

2 – Integer – An integer is a non-decimal number.

$x = 123;

3 – Float – A float is a number with a decimal point.

$x = 10.5;

4 – Boolean – True or False.

$x = true;

5 – Array – Collection of multiple values.

$x = array("value1","value2");

6 – Object – An object is an instance of a class.


7 – NULL – If there is a NULL data type in a variable, then that means the variable does not have any value.

$x = NULL;

If a variable is declared without any value, then the variable is automatically assigned the NULL value.


8 – Resource – Such as Database Connection.


Official Docs of PHP Variables

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