Python removes duplicate elements from the list

From the more easily remembered is the built-in set

L1 = [' B ', ' C ', ' d ', ' B ', ' C ', ' A ', ' a ']
L2 = List (set (L1))
Print L2

There is also a speed difference that is said to be faster and not tested.

L1 = [' B ', ' C ', ' d ', ' B ', ' C ', ' A ', ' a ']
L2 = {}.fromkeys (L1). Keys ()
Print L2

Both have a drawback, and the sorting changes after removing the repeating elements:

[' A ', ' C ', ' B ', ' d ']

If you want to keep their original sort:

Using the Sort method of the list class

L1 = [' B ', ' C ', ' d ', ' B ', ' C ', ' A ', ' a ']
L2 = List (set (L1))
L2.sort (Key=l1.index)
Print L2

Can also be written like this

L1 = [' B ', ' C ', ' d ', ' B ', ' C ', ' A ', ' a ']
L2 = sorted (set (L1), Key=l1.index)
Print L2

You can also use traverse

L1 = [' B ', ' C ', ' d ', ' B ', ' C ', ' A ', ' a ']
L2 = []
For I in L1:
If not I in L2:
L2.append (i)
Print L2

The code above can also be written like this

L1 = [' B ', ' C ', ' d ', ' B ', ' C ', ' A ', ' a ']
L2 = []
[L2.append (i) for I in L1 if not I in L2]
Print L2

This will ensure that the sort is unchanged:

[' B ', ' C ', ' d ', ' a ']

Python removes duplicate elements from the list