Custom Search

Thursday, December 31, 2009

PHP Looping For Loops


Loops execute a block of code a specified number of times, or while a specified condition is true.

--------------------------------------------------------------------------------
The for Loop

The for loop is used when you know in advance how many times the script should run.

Syntax

for (init; condition; increment)
{
code to be executed;
}
Parameters:

•   init: Mostly used to set a counter (but can be any code to be executed once at the beginning of the loop)

•   condition: Evaluated for each loop iteration. If it evaluates to TRUE, the loop continues. If it evaluates to    FALSE, the loop ends.

•    increment: Mostly used to increment a counter (but can be any code to be executed at the end of the loop)

Note: Each of the parameters above can be empty, or have multiple expressions (separated by commas).

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

</body>
</html>

Output:

The number is 1
The number is 2
The number is 3
The number is 4
The number is 5

--------------------------------------------------------------------------------
The foreach Loop


The foreach loop is used to loop through arrays.

Syntax
foreach ($array as $value)
{
code to be executed;
}

For every loop iteration, the value of the current array element is assigned to $value (and the array pointer is moved by one) - so on the next loop iteration, you'll be looking at the next array value.

Example

The following example demonstrates a loop that will print the values of the given array:

<html>
<body>

<?php
$x=array("one","two","three");
foreach ($x as $value)
{
echo $value . "<br />";
}
?>

</body>
</html>

Output:
one
two
three

No comments:

Post a Comment