08-24-2007, 09:49 AM
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| D-Web Genius | | Join Date: Jul 2007
Posts: 1,008
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 Re: Using Arrays in PHP
Traversing Arrays
The most common task with arrays is to do something with every element—for instance, sending mail to each element of an array of addresses, updating each file in an array of filenames, or adding up each element of an array of prices. There are several ways to traverse arrays in PHP, and the one you choose will depend on your data and the task you're performing.
The most common way to loop over elements of an array is to use the foreach construct:
$addresses = array('spam@cyberpromo.net', 'abuse@example.com');
foreach ($addresses as $value) {
echo "Processing $value\n";
}
Processing spam@cyberpromo.net
Processing abuse@example.com
PHP executes the body of the loop (the echo statement) once for each element of $addresses in turn, with $value set to the current element. Elements are processed by their internal order.
An alternative form of foreach gives you access to the current key:
$person = array('name' => 'Fred', 'age' => 35, 'wife' => 'Wilma');
foreach ($person as $key => $value) {
echo "Fred's $key is $value\n";
}
Fred's name is Fred
Fred's age is 35
Fred's wife is Wilma
In this case, the key for each element is placed in $key and the corresponding value is placed in $value.
The foreach construct does not operate on the array itself, but rather on a copy of it. You can insert or delete elements in the body of a foreach loop, safe in the knowledge that the loop won't attempt to process the deleted or inserted elements.
Every PHP array keeps track of the current element you're working with; the pointer to the current element is known as the iterator. PHP has functions to set, move, and reset this iterator. The iterator functions are:
current( )
Returns the element currently pointed at by the iterator
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