python howto remove duplicates

Learn how to remove duplicates from a List in Python.

Example

Remove any duplicates from a List:



mylist = ["a", "b", "a", "c", "c"]mylist = list(dict.fromkeys(mylist))

print(mylist)

Try it Yourself »

Example

Remove any duplicates from a List:

Example Explained

First we have a List that contains duplicates:

A List with Duplicates



mylist = ["a", "b", "a", "c", "c"]





mylist = list(dict.fromkeys(mylist))

print(mylist)

A List with Duplicates

Create a dictionary,

using the List items as keys. This will automatically remove any duplicates

because dictionaries cannot have duplicate keys.

Create a Dictionary





mylist = ["a", "b", "a", "c", "c"]



mylist = list(dict.fromkeys(mylist))

print(mylist)

Create a Dictionary

Then, convert the dictionary back into a list:

Convert Into a List





mylist = ["a", "b", "a", "c", "c"]



mylist = list(dict.fromkeys(mylist))

print(mylist)

Convert Into a List

Now we have a List without any duplicates, and it has the same order as the

original List.

Print the List to demonstrate the result

Print the List





mylist = ["a", "b", "a", "c", "c"]

mylist = list(dict.fromkeys(mylist))

print(mylist)

Print the List

Create a Function

If you like to have a function where you can send your lists, and get them

back without duplicates, you can create a function and insert the code from the

example above.

Example



def my_function(x):  return list(dict.fromkeys(x))mylist =

my_function(["a", "b", "a", "c", "c"])

print(mylist)

Try it Yourself »

Example

Example Explained

Create a function that takes a List as an argument.

Create a Function



def my_function(x):

  return list(dict.fromkeys(x))mylist =

my_function(["a", "b", "a", "c", "c"])

print(mylist)

Create a Function

Create a dictionary, using this List items as keys.

Create a Dictionary



def my_function(x):

  return list(dict.fromkeys(x))mylist =

my_function(["a", "b", "a", "c", "c"])

print(mylist)

Create a Dictionary

Convert the dictionary into a list.

Convert Into a List



def my_function(x):

  return list(dict.fromkeys(x))mylist =

my_function(["a", "b", "a", "c", "c"])

print(mylist)

Convert Into a List

Return the list

Return List



def my_function(x):

  return list(dict.fromkeys(x))mylist =

my_function(["a", "b", "a", "c", "c"])

print(mylist)

Return List

Call the function, with a list as a parameter:

Call the Function



def my_function(x):

  return list(dict.fromkeys(x))

mylist = my_function(["a", "b", "a", "c", "c"])

print(mylist)

Call the Function

Print the result:

Print the Result



def my_function(x):

  return list(dict.fromkeys(x))

mylist = my_function(["a", "b", "a", "c", "c"])

print(mylist)

Print the Result