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  • Python
  • Remove List 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)

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)

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)

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)

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)

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)

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 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)

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)

Return the list

Return List

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

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

print(mylist)

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)

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)
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