http://stackoverflow.com/questions/6810862/word-letter-count-in-an-associative-array

test.php

<?php

$input = "this is my sample which is sorted and simple";

echo "Input: ".$input."<br/>";

foreach(explode(" ",$input) as $in)
{	
	if(isset($firstarray[strlen($in)][$in]))
		$firstarray[strlen($in)][$in]++;
	else
		$firstarray[strlen($in)][$in] = 1;
	ksort($firstarray[strlen($in)]);
}

ksort($firstarray);
print_r($firstarray);

?>

test2.php

<?php

/**
* Better use arrays by reference
* http://php.net/manual/en/language.references.php
*
*/

$input = "this is my sample which is sorted and simple";

echo "Input: ".$input."<br/>";

foreach(explode(" ",$input) as $in)
{	
	if(isset($firstarray[strlen($in)][$in]))
		$firstarray[strlen($in)][$in]++;
	else
		$firstarray[strlen($in)][$in] = 1;
}

ksort($firstarray);
foreach($firstarray as &$secarray)
{
	ksort($secarray);
}
print_r($firstarray);

?>