what is array.

The array() function is used for creating array.

<?php
$name = array("john", "roy", "bolt");
echo "names " . $name[0] . ", " . $name[1] . " and " . $name[2] . ".";
?>

Associative arrays are arrays that use named keys that you assign to them.
There are two ways to create an associative array:

$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
or
$age['Peter'] = "35";
$age['Ben'] = "37";
$age['Joe'] = "43";

The named keys can then be used in a script:

<?php
$age = array("Peter"=>"35", "Ben"=>"37", "Joe"=>"43");
echo "Peter is " . $age['Peter'] . " years old.";
?>