If/Else Conditional Statment

Posted on May 3, 2011

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Has someone ever told you, “if you work hard, then you will succeed”? And what happens if you do not work hard? Well, you fail! This is an example of an if/else conditional statement.

  • If you work hard then you will succeed.
  • Else, if you do not work hard, then you will fail.

How does this translate into something useful for PHP developers? Well consider this:

Someone comes to your website and you want to ask this visitor her name if it is her first time coming to your site. With an if statement this is easy. Simply have a conditional statement to check, “are you visiting for the first time”. If the condition is true, then take them to the “Insert Your Name” page, else let her view the website as normal because you have already asked her for her name in the past.

If/Else an Example

Using these conditional statements can add a new layers of “cool” to your website. Here’s the basic form of an if/else statement in PHP.

PHP Code:

$number_three = 3;

if ( $number_three == 3 ) {
	echo "The if statement evaluated to true";
} else {
	echo "The if statement evaluated to false";
}

Display:

The if statement evaluated to true

This is a lot to digest in one sitting, so let us step through the code, line by line.

  • We first made a PHP variable called $number_three and set it equal to 3.
  • In this example we compared a variable to an integer value. To do such a comparison we use “==“, which in English means “Is Equal To”.
  • $number_three is indeed Equal To 3 and so this statement will evaluate to true.
  • All code that is contained between the opening curly brace “{” that follows the if statement and the closing curly brace “}” will be executed when the if statement is true.
  • The code contained within the else segment will not used.

Execute Else Code with False

On the other hand, if the if statement was false, then the code contained in the else segment would have been executed. Note that the code within the if and else cannot both be executed, as the if statement cannot evaluate to both true and false at one time! Here is what would happen if we changed to $number_three to anything besides the number 3.

PHP Code:

$number_three = 421;

if ( $number_three == 3 ) {
	echo "The if statement evaluated to true";
} else {
	echo "The if statement evaluated to false";
}

Display:

The if statement evaluated to false

The variable was set to 421, which is not equal to 3 and the if statement was false. As you can see, the code segment contained within the else was used in this case.

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Posted in: PHP