Python methods for removing repeating elements in a list

This example describes how Python removes repeating elements from a list. Share to everyone for your reference. Specific as follows:

It's easier to remember with 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 ']

Hopefully this article will help you with Python programming.

