PHP do…while
Summary: in this tutorial, you will learn how to use the PHP do...while loop statement to execute a code block repeatedly.
Introduction to PHP do…while loop statement
The PHP do...while statement allows you to execute a code block repeatedly based on a Boolean expression. Here’s the syntax of the PHP do-while statement:
do {
statement;
} while (expression);
Code language: HTML, XML (xml)
Unlike the while statement, PHP evaluates the expression at the end of each iteration. It means that the loop always executes at least once, even the expression is false before the loop enters.
The following flowchart illustrates how the do...while statement works:
do…while vs. while
The differences between the do...while and while statements are:
- PHP executes the statement in
do...whileat least once, whereas it won’t execute thestatementin thewhilestatement if theexpressionisfalse. - PHP evaluates the
expressionin thedo...whilestatement at the end of each iteration. Conversely, PHP evaluates theexpressionin thewhilestatement at the beginning of each iteration.
PHP do…while loop statement example
In the following example, the code block inside the do...while loop statement executes precisely one time.
$i = 0;
do {
echo $i;
} while ($i > 0);
Code language: HTML, XML (xml)
The code inside the loop body executes first to display the variable $i. Because the value of the $i is 0, the condition is met, the loop stops.
In the following example, the code block inside the do...while loop executes ten times:
$i = 10;
do {
echo $i . '<br>';
i--;
} while ($i > 0);
Code language: HTML, XML (xml)
In this tutorial, you have learned how to use PHP do...while loop statement to execute a code block repeatedly until a condition is false.