Monday, 22 August 2011

PHP If...Else Statements


PHP If...Else Statements


Conditional statements are used to perform different actions based on different conditions.

Conditional Statements

Very often when you write code, you want to perform different actions for different decisions.
You can use conditional statements in your code to do this.
In PHP we have the following conditional statements:
  • if statement - use this statement to execute some code only if a specified condition is true
  • if...else statement - use this statement to execute some code if a condition is true and another code if the condition is false
  • if...elseif....else statement - use this statement to select one of several blocks of code to be executed
  • switch statement - use this statement to select one of many blocks of code to be executed

The if Statement

Use the if statement to execute some code only if a specified condition is true.

Syntax

if (conditioncode to be executed if condition is true;
The following example will output "Have a nice weekend!" if the current day is Friday:
PHP Code


$d=date("D");
if ($d=="Fri") echo "Have a nice weekend!";




Notice that there is no ..else.. in this syntax. The code is executed only if the specified condition is true.

The if...else Statement

Use the if....else statement to execute some code if a condition is true and another code if a condition is false.

Syntax

PHP Code

if (condition)
  code to be executed if condition is true;
else
  code to be executed if condition is false


Example

The following example will output "Have a nice weekend!" if the current day is Friday, otherwise it will output "Have a nice day!":

PHP Code

 $d=date("D");
if ($d=="Fri")
  echo "Have a nice weekend!";
else
  echo "Have a nice day!";




If more than one line should be executed if a condition is true/false, the lines should be enclosed within curly braces:

PHP Code

$d=date("D");
if ($d=="Fri")
  {
  echo "Hello!";
  echo "Have a nice weekend!";
  echo "See you on Monday!";
  }







The if...elseif....else Statement

Use the if....elseif...else statement to select one of several blocks of code to be executed.

Syntax


PHP Code

if (condition)
  code to be executed if condition is true;
elseif (condition)
  code to be executed if condition is true;else
  code to be executed if condition is false;


Example


<?php
$d=date("D");
if ($d=="Fri")
  echo "Have a nice weekend!";
elseif ($d=="Sun")
  echo "Have a nice Sunday!";
else
  echo "Have a nice day!";
?>

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