In [1]:

    

l = [3, 3, 2, 1, 5, 1, 4, 2, 3]


    

In [2]:

    

print(set(l))


    

    




{1, 2, 3, 4, 5}

In [3]:

    

print(list(set(l)))


    

    




[1, 2, 3, 4, 5]

In [4]:

    

print(dict.fromkeys(l))


    

    




{3: None, 2: None, 1: None, 5: None, 4: None}

In [5]:

    

print(list(dict.fromkeys(l)))


    

    




[3, 2, 1, 5, 4]

In [6]:

    

print(sorted(set(l), key=l.index))


    

    




[3, 2, 1, 5, 4]

In [7]:

    

l_2d = [[1, 1], [0, 1], [0, 1], [0, 0], [1, 0], [1, 1], [1, 1]]


    

In [8]:

    

# l_2d_unique = list(set(l_2d))
# TypeError: unhashable type: 'list'


    

In [9]:

    

# l_2d_unique_order = dict.fromkeys(l_2d)
# TypeError: unhashable type: 'list'


    

In [10]:

    

def get_unique_list(seq):
    seen = []
    return [x for x in seq if x not in seen and not seen.append(x)]


    

In [11]:

    

print(get_unique_list(l_2d))


    

    




[[1, 1], [0, 1], [0, 0], [1, 0]]

In [12]:

    

print(get_unique_list(l))


    

    




[3, 2, 1, 5, 4]

In [13]:

    

print([x for x in set(l) if l.count(x) > 1])


    

    




[1, 2, 3]

In [14]:

    

print([x for x in dict.fromkeys(l) if l.count(x) > 1])


    

    




[3, 2, 1]

In [15]:

    

print(sorted([x for x in set(l) if l.count(x) > 1], key=l.index))


    

    




[3, 2, 1]

In [16]:

    

print([x for x in l if l.count(x) > 1])


    

    




[3, 3, 2, 1, 1, 2, 3]

In [17]:

    

def get_duplicate_list(seq):
    seen = []
    return [x for x in seq if not seen.append(x) and seen.count(x) == 2]


    

In [18]:

    

def get_duplicate_list_order(seq):
    seen = []
    return [x for x in seq if seq.count(x) > 1 and not seen.append(x) and seen.count(x) == 1]


    

In [19]:

    

print(get_duplicate_list(l_2d))


    

    




[[0, 1], [1, 1]]

In [20]:

    

print(get_duplicate_list_order(l_2d))


    

    




[[1, 1], [0, 1]]

In [21]:

    

print(get_duplicate_list(l))


    

    




[3, 1, 2]

In [22]:

    

print(get_duplicate_list_order(l))


    

    




[3, 2, 1]

In [23]:

    

print([x for x in l_2d if l_2d.count(x) > 1])


    

    




[[1, 1], [0, 1], [0, 1], [1, 1], [1, 1]]