Operators, Conditionals, and PHP Decision-Making - The else statement

The optional else statement (see Example 4-6) provides a default block of code that executes if the condition returned is FALSE. else cannot be used without an if statement, as it doesn't take a conditional itself. So, else and if have to always be together in your code.

Example 4-6. else and if statements

if ($username == "Admin"){
    echo ('Welcome to the admin page.');
}
else {
    echo ('Welcome to the user page.');
}

Remember to close out the code block from the if conditional when you've used braces to start your block of code. Similar to the if block, the else block should also use curly braces to begin and end the code.

The elseif statement

All of this is great except for when you want to test for several conditions simultaneously. To do this, you can use the elseif statement. It allows for testing of additional conditions until one is found to be true or until you hit the else block. Each elseif has its own code block that comes directly after the elseif condition. The elseif must come after the if statement and before an else statement if one exists.

The elseif structure is a little complicated, but Example 4-7 should help you understand it.

Example 4-7. Checking multiple conditions

if ($username == "Admin"){
    echo ('Welcome to the admin page.');
}
elseif ($username == "Guest"){
    echo ('Please take a look around.');
}
else {
    echo ("Welcome back, $username.");
}

Here you can check for two conditions and take different actions based on each of the values for $username. Then you also have the option to do something else if the $username isn't one of the first two.

The next construct builds on the concepts of the if/ else statement, but it allows you to efficiently check the results of an expression to many values without having a separate if/else for each value.

Please check back next week for the conclusion to this article.