Convert a multi-dimentional array to a single dimension array. #array_flatten

functions.php

/*
 * Convert a multi-dimentional array to a single dimension array.
 */
public static function array_flatten( array $arr ) {
	
	$flattened = array();
	
	foreach ( $arr as $key => $value ) {
		
		if ( is_array( $value ) ) {
			
			$flattened = array_merge( $flattened, self::array_flatten( $value ) );
			
		} else {
			$flattened[ $key ] = $value;
		}
	}
	
	return $flattened;
}