PHP Tutorial - PHP if

• « Previous
• Next »

We can make simple Decisions with the if Statement.

Syntax

The basic form of an if construct is as follows:

if (   expression  ) { 
  // Run this code 
} 
// More code here   

If you only have one statement of code to execute, you can do without the braces entirely. It's a readability issue.

So, these two code chunks are the same:

if ($banned) {
       print "You are banned!";
}

if ($banned) print "You are banned!";

Note for if statement

If the expression inside the parentheses evaluates to true, the code between the braces is run.

If the expression evaluates to false, the code between the braces is skipped.

Example - if statement

Here is a working example for if statement:

<?php
        $Age = 20;
        if ($Age < 18) {
                print "under 18\n";
        } else {
                print "You're not under 18\n";
        }
 ?>

The code above generates the following result.

Example - if statement with more conditions

Here's another example that uses the >= (greater than or equal) and <= (less than or equal) comparison operators, as well as the && (and) logical operator:

<?PHP
     $myValue = 23; 

     if ( $myValue  >= 10  &&  $myValue  <= 20 ) { 
       echo "between 10 and 20."; 
     }   
?>

Example nested if

Here's the previous example rewritten to use an if statement inside another if statement:

<?PHP
     $myValue = 23; 
     if ( $myValue  >= 10 ) { 
       if ( $myValue  <= 20 ) { 
         echo "10 and 20."; 
       } 
     }   
?>

PHP if else

We can providing an alternative choice with the else statement.

Syntax for if else statement

The PHP if else statement has the following syntax.

if(condition_0){
...
}else{
...
}

or

if(condition_0){
...
}elseif (condition_1){

}elseif (condition_2){

}else{
...
}

Note for if else statement

else statement lets you run one block of code if an expression is true, and a different block of code if the expression is false.

Example - PHP if else statement

<?PHP
$myValue = 23; 

if ( $myValue  >= 10 ) { 
 echo "greater than 10."; 
} else { 
 echo "Less than 10!"; 
}   
?>

The code above generates the following result.

Example - PHP if else statement ladder

You can even combine the else statement with another if statement to make as many alternative choices as you like:

<?php
       
       $Age = 23; 
       if ($Age < 10) {
               print "You're under 10";
       } elseif ($Age < 20) {
               print "You're under 20";
       } elseif ($Age < 30) {
               print "You're under 30";
       } elseif ($Age < 40) {
               print "You're under 40";
       } else {
               print "You're over 40";
       }
?>

The code above generates the following result.

Example if-elseif-else

The following code shows how to use if-elseif-else statement.

<?php
  $name = "Jack";
  if($name == "")
  {
    print("You have no name.");
  }
  elseif(($name == "leon") OR ($name == "Leon"))
  {
    print("Hello, Leon!");
  }
  else
  {
    print("Your name is '$name'.");
  }
?>

The code above generates the following result.

• Next »
• « Previous