PHP array - How to loop through a PHP array

PHP array FAQ: How do I iterate (loop) through a PHP array?

Answer: The easiest way to loop through a PHP array is to use the PHP foreach operator. If you have a simple one-dimensional array, like the $argv array which lets you access command line arguments, you can loop through it like this:

#!/usr/bin/php
<?php
// loop through each element in the $argv array
foreach($argv as $value)
{
  echo "$value\n";
}
?>

If I save this file as argtest.php, and then run it, like this:

php argtest.php foo bar baz

I'll get the following output from the script:

argtest.php
foo
bar
baz

I can also loop through a PHP array by accessing the array key and value, like this:

#!/usr/bin/php
<?php
// loop through each element in the $argv array
foreach($argv as $key => $value)
{
  echo "$key = $value\n";
}
?>

For this example, this array key/value approach results in the following output:

0 = argtest.php
1 = foo
2 = bar
3 = baz

Using the $argv array here isn't a great example of why you might want to access the array elements as key/value pairs, but I'm writing this article for myself, and all I really need is a reminder of this PHP foreach key/value syntax.

Okay, okay, this example makes more sense if you have a two-dimensional array like this:

$al = array(
  'first_name' => 'Alvin',
  'last_name' => 'Alexander'
);