#https://docs.python.org/3.5/howto/sorting.html?highlight=sort

#In Python 3.2, the function was added to the module in the standard library

 

 

# compare function

def mycmp(x,y):

    if len(x) == len(y):

        if x== y :

            return 0

        elif x < y:

            return -1

        else:

            return 1

    else:

        return len(x) - len(y)

#transfer compare func to key

def cmp_to_key(mycmp):

    '''Convert a cmp= function into a key= function'''

    class K(object):

        def __init__(self, obj, *args):

            self.obj = obj

        def __lt__(self, other):

            return mycmp(self.obj, other.obj) < 0

        def __gt__(self, other):

            return mycmp(self.obj, other.obj) > 0

        def __eq__(self, other):

            return mycmp(self.obj, other.obj) == 0

        def __le__(self, other):

            return mycmp(self.obj, other.obj) <= 0

        def __ge__(self, other):

            return mycmp(self.obj, other.obj) >= 0

        def __ne__(self, other):

            return mycmp(self.obj, other.obj) != 0

    return K

#first do unique

line_list = list(np.unique(line_list))

#sort the string list

res = line_list.sort(key = cmp_to_key(mycmp))