Creating a PHP Looping Statement

by Darren Hedlund
Monday, 21st November 2005

Creating a PHP loop to go through a certain part of code to gather more information than just a single part of data is essential to many programmers.

These methods are used for searching iside a database, counting through information, and other useful functions.

Below are some simple ways that you can create a while lopp in PHP.

The while Statement

The while statement will execute a block of code if and as long a condition is true.

Syntax
while (condition)
code to be executed;

Example
The following example demonstrates a loop that will continue to run as long as the variable i is less than, or equal to 5. i will increase by 1 each time the loop runs:

<html>
<body><?php
$i=1;
while($i<=5)
{
echo "The number is " . $i . "<br />";
$i++;
}
?></body>
</html>

The do...while Statement

The do...while statement will execute a block of code at least once - it then will repeat the loop as long as a condition is true.

Syntax
do
{
code to be executed;
}
while (condition);

Example
The following example will increment the value of i at least once, and it will continue incrementing the variable i while it has a value of less than 5:

<html>
<body><?php
$i=0;
do
{
$i++;
echo "The number is " . $i . "<br />";
}
while ($i<5);
?></body>
</html>

The for Statement

The for statement is used when you know how many times you want to execute a statement or a list of statements.

Syntax
for (initialization; condition; increment)
{
code to be executed;
}

Note: The for statement has three parameters. The first parameter is for initializing variables, the second parameter holds the condition, and the third parameter contains any increments required to implement the loop. If more than one variable is included in either the initialization or the increment section, then they should be separated by commas. The condition must evaluate to true or false.

Example
The following example prints the text "Hello World!" five times:

<html>
<body><?php
for ($i=1; $i<=5; $i++)
{
echo "Hello World!<br />";
}
?></body>
</html>

Darren Hedlund is a freelance Web developer, writer, and data analyst. Darren has a graduate degree in Computer Information Science and has spent the last 15 years developing application and environments from hand held, windows, web, virtual science, gaming, artificial intelligence and graphics design. Darren's coding knowledge ranges from C+, Visual Basic, .NET, PHP, JSP, REXX, KIXX, and many others. His graphical and environmental knowledge stems in Macromedia Flash, 3D studio Max, Curious Labs Poser, Adobe Photoshop, and many others. Darren works in many platforms ranging from database, visual design, and, system development.
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