Get Unique Values From a List in Python

Get Unique Values From a List in Python

Hassan Saeed Dec-10, 2020 Oct-17, 2020 Python Python List
  1. Use dict.fromkeys to Get Unique Values From a List in Python
  2. Use a New List to Get Unique Values From the Original List in Python
  3. Use set() to Get Unique Values From a List in Python

This tutorial discusses methods to get unique values from a list in Python.

Use dict.fromkeys to Get Unique Values From a List in Python

We can use the dict.fromkeys method of the dict class to get unique values from a Python list. This method preserves the original order of the elements and keeps only the first element from the duplicates. The below example illustrates this.

inp_list = [2, 2, 3, 1, 4, 2, 5]
unique_list = list(dict.fromkeys(inp_list))
print(unique_list)

Output:

[2, 3, 1, 4, 5]

Use a New List to Get Unique Values From the Original List in Python

Another method to get unique values from a list in Python is to create a new list and add only unique elements to it from the original list. This method preserves the original order of the elements and keeps only the first element from the duplicates. The below example illustrates this.

inp_list = [2, 2, 3, 1, 4, 2, 5]
unique_list = []
[unique_list.append(x) for x in inp_list if x not in unique_list]
unique_list

Output:

[2, 3, 1, 4, 5]

Use set() to Get Unique Values From a List in Python

Set in Python holds unique values only. We can insert the values from our list to a set to get unique values. However, this method does not preserve the order of the elements. The below example illustrates this.

inp_list = [2, 2, 3, 1, 4, 2, 5]
unique_list = list(set(inp_list))
print(unique_list)

Output:

[1, 2, 3, 4, 5]

Note that the order of elements is not preserved as in the original list.

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