# Python | Remove repeated sublists from given list

Given a list of lists, write a Python program to remove all the repeated sublists (also with different order) from given list.

**Examples:**

Attention geek! Strengthen your foundations with the **Python Programming Foundation** Course and learn the basics.

To begin with, your interview preparations Enhance your Data Structures concepts with the **Python DS** Course. And to begin with your Machine Learning Journey, join the **Machine Learning - Basic Level Course**

Input :[[1], [1, 2], [3, 4, 5], [2, 1]]Output :[[1], [1, 2], [3, 4, 5]]Input :[['a'], ['x', 'y', 'z'], ['m', 'n'], ['a'], ['m', 'n']]Output :[['a'], ['x', 'y', 'z'], ['m', 'n']]

**Approach #1 :** *Set* comprehension + Unpacking

Our first approach is to use *set* comprehension with *sorted* tuple. In every iteration in the list, we convert the current sublist to a sorted tuple, and return a set of all these tuples, which in turn eliminates all repeated occurrences of the sublists and thus, remove all repeated rearranged sublists.

`# Python3 program to Remove repeated ` `# unordered sublists from list` ` ` `def` `Remove(lst):` ` ` `return` `([` `list` `(i) ` `for` `i ` `in` `{` `*` `[` `tuple` `(` `sorted` `(i)) ` `for` `i ` `in` `lst]}]) ` ` ` `# Driver code` `lst ` `=` `[[` `1` `], [` `1` `, ` `2` `], [` `3` `, ` `4` `, ` `5` `], [` `2` `, ` `1` `]]` `print` `(Remove(lst))` |

**Output:**

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

**Approach #2 :** Using *map()* with *set* and *sorted* tuples.

`# Python3 program to Remove repeated ` `# unordered sublists from list` ` ` `def` `Remove(lst):` ` ` `return` `list` `(` `map` `(` `list` `, (` `set` `(` `map` `(` `lambda` `x: ` `tuple` `(` `sorted` `(x)), lst)))))` ` ` `# Driver code` `lst ` `=` `[[` `1` `], [` `1` `, ` `2` `], [` `3` `, ` `4` `, ` `5` `], [` `2` `, ` `1` `]]` `print` `(Remove(lst))` |

**Output:**

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

**With maintaining order –**

**Approach #3 :** Using sorted tuple as hash

First, we initialize an empty list as ‘res’ and a set as ‘check’. Now, For each sublist in the list, convert the sublist to sorted tuple and save it in ‘hsh’. Then check if hsh is present in check or not. If not, append the current sublist to ‘.res’ and ‘hsh’ to ‘check’. This way it would be easier to maintain the order to sublists.

`# Python3 program to Remove repeated ` `# unordered sublists from list` ` ` `def` `Remove(lst):` ` ` `res ` `=` `[]` ` ` `check ` `=` `set` `()` ` ` ` ` `for` `x ` `in` `lst:` ` ` `hsh ` `=` `tuple` `(` `sorted` `(x))` ` ` `if` `hsh ` `not` `in` `check:` ` ` `res.append(x)` ` ` `check.add(hsh)` ` ` ` ` `return` `res` ` ` `# Driver code` `lst ` `=` `[[` `1` `], [` `1` `, ` `2` `], [` `3` `, ` `4` `, ` `5` `], [` `2` `, ` `1` `]]` `print` `(Remove(lst))` |

**Output:**

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