PHP - While Loops
Loops execute a block of code a specified number of times, or while a specified condition is true. Often when you write code, you want the same block of code to run over and over again in a row. Instead of adding several almost equal lines in a script we can use loops to perform a task like this.
In PHP, we have the following looping statements:
- while - loops through a block of code while a specified condition is true
- do...while - loops through a block of code once, and then repeats the loop as long as a specified condition is true
- for - loops through a block of code a specified number of times
- foreach - loops through a block of code for each element in an array
The while loop executes a block of code while a condition is true.
The While Loop PHP Syntax
while (condition)
{
code to be executed;
}
The While Loop PHP Example
The example below defines a loop that starts with i=1. The loop will continue to run as long as 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 While Loop PHP Output
The number is 1
The number is 2
The number is 3
The number is 4
The number is 5
The do...while statement will always execute the block of code once, it will then check the condition, and repeat the loop while the condition is true.
The do...while PHP Syntax
do
{
code to be executed;
}
while (condition);
The do...while PHP Example
The example below defines a loop that starts with i=1. It will then increment i with 1, and write some output. Then the condition is checked, and the loop will continue to run as long as i is less than, or equal to 5:
<html>
<body>
<?php
$i=1;
do
{
$i++;
echo "The number is " . $i . "<br />";
}
while ($i<=5);
?>
</body>
</html>
The do...while Output
The number is 2
The number is 3
The number is 4
The number is 5
The number is 6
