PHP Looping - While Loops
Loops execute a block of code a specified number of times, or while a specified condition is true.
PHP Loops
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
The while loop executes a block of code while a condition is true.
Syntax
while (condition)
{
code to be executed;
} |
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>
|
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
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.
Syntax
do
{
code to be executed;
}
while (condition);
|
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>
|
Output:
The number is 2
The number is 3
The number is 4
The number is 5
The number is 6 |
The for loop and the foreach loop will be explained in the next chapter.
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