Quick & dirty is-array-associative test

is_associative_array.php

/**
 * Test whether/not $array is associative
 * 
 * Got annoyed when I saw a coworker using the accepted answer at http://stackoverflow.com/questions/173400/how-to-check-if-php-array-is-associative-or-sequential?page=1&tab=active#tab-top
 * It seems overly complicated, and fails if the linear array's keys aren't contiguous (as do several other solutions I found).
 * 
 * Sample test arrays: 
 * ----------------------------------------
 * 
 * $empty_array = array ( );
 * $linear_array = array ( 0 => 'first', 1 => 'second', 2 => 'third' );
 * $associative_array = array ( 'a' => 'apple', 'b' => 'banana', 'c' => 'cherry' );
 * $linear_array_with_non_contiguous_indexes = array ( 2 => 'foo', 42 => 'bar' );
 * $associative_array_with_integer_keys = array ( 0 => 'dread', 'i' => 'am the law' );
 * 
 * @param array $array
 * @return boolean
 */
function is_associative_array(array $array) { 
	foreach (array_keys($array) as $key) {
		if (is_string($key)) {
			return true;
		}
	}
	
	return false;
}

Wonder if this should return true if the array is empty? Indeterminate at that point, though...