def rank_as_string(list1, alphanum_index):
    """
    Convert a ranked list of items into a string of characters 
    based on a given dictionary `alph` of the format that contains 
    the ranked items and a random alphanumeric to represent it.
    
    Parameters
    ----------
        list1 : list
            A list of rankings to be converted to characters
            
        alph : dict
            A dictionary containing the items in list1 as keys
            and unique characters as the values.
    """
    return ''.join([alphanum_index[l] for l in list1])