|
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
|