PHP switch
Summary: in this tutorial, you will learn about the PHP switch statement that executes a code block by matching an expression with multiple values.
Introduction to the PHP switch statement
When the value of a single variable determines the number of different choices, you can use the if...elseif
statement.
Suppose that you’re building a website whose users have many roles like admin, editor, author, and subscriber.
The following example uses an if elseif
statement to display a different message based on the role of the user:
$role = 'subscriber';
$message = '';
if ('admin' === $role) {
$message = 'Welcome, admin!';
} elseif ('editor' === $role) {
$message = 'Welcome! You have some pending articles to edit';
} elseif ('author' === $role) {
$message = 'Welcome! Do you want to publish the draft article?';
} elseif ('subscriber' === $role) {
$message = 'Welcome! Check out some new articles.';
} else {
$message = 'Sorry! You are not authorized to access this page';
}
echo $message;
Code language: HTML, XML (xml)
Output:
Welcome! Check out some new articles.
Code language: JavaScript (javascript)
When the value of a single variable specifies the number of different choices, it’s much cleaner to use the switch
statement like this:
$role = 'admin';
$message = '';
switch ($role) {
case 'admin':
$message = 'Welcome, admin!';
break;
case 'editor':
$message = 'Welcome! You have some pending articles to edit';
break;
case 'author':
$message = 'Welcome! Do you want to publish the draft article?';
break;
case 'subscriber':
$message = 'Welcome! Check out some new articles.';
break;
default:
$message = 'You are not authorized to access this page';
}
echo $message;
Code language: HTML, XML (xml)
The following illustrates the syntax of the switch
statement:
switch (expression) {
case value1:
// code block 1
break;
case value2:
// code block 2
break;
case value3:
// code block 3
break;
default:
// default code block
}
Code language: HTML, XML (xml)
The switch
statement compares an expression
with the value in each case.
If the expression equals a value in a case, e.g., value1
, PHP executes the code block in the matching case until it encounters the first break
statement.
If there’s no match and the default
is available, PHP executes all statements following the default
keyword.
In case the default
is not specified, and there’s no match, the control is passed to the statement that follows the switch
statement.
The following flowchart illustrates how the switch
statement works:
Combining cases
Since PHP executes the switch
statement from the matching case label till it encounters the break
statement, you can combine several cases in one.
The following example uses the switch statement and combines the cases of 'editor'
and 'author'
:
$message = '';
$role = 'author';
switch ($role) {
case 'admin':
$message = 'Welcome, admin!';
break;
case 'editor':
case 'author':
$message = 'Welcome! Do you want to create a new article?';
break;
case 'subscriber':
$message = 'Welcome! Check out some new articles.';
break;
default:
$message = 'You are not authorized to access this page';
}
echo $message;
Code language: HTML, XML (xml)
Output:
Welcome! Do you want to create a new article?
Code language: PHP (php)
In this example, if the role
is editor
or author, it’ll show the same message.
PHP switch statement’s alternative syntax
PHP also supports the alternative syntax for the switch
statement as follows:
switch (expression):
case value1:
// code block 1
break;
case value2:
// code block 2
break;
default:
// default code block
break;
endswitch;
Code language: HTML, XML (xml)
The alternative syntax is suitable for mixing with the HTML code.
Summary
- Use PHP
switch
statement instead of a series ofif
statements on the same expression.