How to get unique values from a list in Python

There are various ways in which you can get unique values from a list in Python.

Let's take a look at a few examples.

number_list = [4, 2, 1, 4, 3, 2]

unique_values = list(set(number_list))

print(unique_values)

In the above example, we converted the list to a set and then back to a list to get the list of unique numbers.

Note: The output is a order list of unique values.

number_list = [4, 2, 1, 4, 3, 2]

unique_values = [no for i, no in enumerate(number_list) if no not in number_list[:i]]

print(unique_values)

Note: This will provide a list that is in order and has unique values.

number_list = [4, 2, 1, 4, 3, 2]

unique_values = list(dict.fromkeys(number_list))

print(unique_values)

Note: This will provide a list that is in order and has unique values.

from collections import Counter

city_list = [
    "Tokyo", "London", "New York", "Paris", "Sydney",
    "Cairo", "Tokyo", "Beijing", "New York", "Moscow",
    "Rio de Janeiro", "London", "Sydney", "Mumbai", "Lima"
]

city_counts = Counter(city_list)
unique_cities = [city for city, count in city_counts.items() if count == 1]

print(unique_cities)

Human-Written Content: This article was demonstrated by a human, not AI.

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References:

set: https://docs.python.org/3/library/stdtypes.html#set

List Comprehensions: https://docs.python.org/3/tutorial/datastructures.html#list-comprehensions

dict.fromkeys: https://docs.python.org/3/library/stdtypes.html#dict.fromkeys

collections.Counter: https://docs.python.org/3/library/collections.html#collections.Counter