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Python | Get unique values from a list
• Difficulty Level : Easy
• Last Updated : 08 Feb, 2021

Given a list, print all the unique numbers in any order.
Examples:

```Input : 10 20 10 30 40 40
Output : 10 20 30 40

Input : 1 2 1 1 3 4 3 3 5
Output : 1 2 3 4 5  ```

Method 1 : Traversal of list

Using traversal, we can traverse for every element in the list and check if the element is in the unique_list already if it is not over there, then we can append it in the unique_list. This is done using one for loop and other if statement which check if the value is in the unique list or not which is equivalent to another for loop.

## Python

 `# Python program to check if two``# to get unique values from list``# using traversal` `# function to get unique values``def` `unique(list1):` `    ``# intilize a null list``    ``unique_list ``=` `[]``    ` `    ``# traverse for all elements``    ``for` `x ``in` `list1:``        ``# check if exists in unique_list or not``        ``if` `x ``not` `in` `unique_list:``            ``unique_list.append(x)``    ``# print list``    ``for` `x ``in` `unique_list:``        ``print` `x,``    ` `  `  `# driver code``list1 ``=` `[``10``, ``20``, ``10``, ``30``, ``40``, ``40``]``print``(``"the unique values from 1st list is"``)``unique(list1)`  `list2 ``=``[``1``, ``2``, ``1``, ``1``, ``3``, ``4``, ``3``, ``3``, ``5``]``print``(``"\nthe unique values from 2nd list is"``)``unique(list2)`

Output:

```the unique values from 1st list is
10 20 30 40
the unique values from 2nd list is
1 2 3 4 5```

Method 2 : Using Set

Using set() property of Python, we can easily check for the unique values. Insert the values of the list in a set. Set only stores a value once even if it is inserted more then once. After inserting all the values in the set by list_set=set(list1), convert this set to a list to print it.

## Python

 `# Python program to check if two``# to get unique values from list``# using set` `# function to get unique values``def` `unique(list1):``    ` `    ``# insert the list to the set``    ``list_set ``=` `set``(list1)``    ``# convert the set to the list``    ``unique_list ``=` `(``list``(list_set))``    ``for` `x ``in` `unique_list:``        ``print` `x,``    `  `# driver code``list1 ``=` `[``10``, ``20``, ``10``, ``30``, ``40``, ``40``]``print``(``"the unique values from 1st list is"``)``unique(list1)`  `list2 ``=``[``1``, ``2``, ``1``, ``1``, ``3``, ``4``, ``3``, ``3``, ``5``]``print``(``"\nthe unique values from 2nd list is"``)``unique(list2)`

Output:

```the unique values from 1st list is
40 10 20 30
the unique values from 2nd list is
1 2 3 4 5```

Method 3 : Using numpy.unique

Using Python’s import numpy, the unique elements in the array are also obtained. In first step convert the list to x=numpy.array(list) and then use numpy.unique(x) function to get the unique values from the list. numpy.unique() returns only the unique values in the list.

## Python3

 `#Ppython program to check if two``# to get unique values from list``# using numpy.unique``import` `numpy as np` `# function to get unique values``def` `unique(list1):``    ``x ``=` `np.array(list1)``    ``print``(np.unique(x))``    `  `# driver code``list1 ``=` `[``10``, ``20``, ``10``, ``30``, ``40``, ``40``]``print``(``"the unique values from 1st list is"``)``unique(list1)`  `list2 ``=``[``1``, ``2``, ``1``, ``1``, ``3``, ``4``, ``3``, ``3``, ``5``]``print``(``"\nthe unique values from 2nd list is"``)``unique(list2)`

Output

```the unique values from 1st list is
[10 20 30 40]

the unique values from 2nd list is
[1 2 3 4 5]```

Method #4: Using collections.Counter()

Using python import Counter() from collections print all the keys of Counter elements or we print directly by using “*” symbol.

Below is the implementation of above approach.

## Python3

 `# Python program to check if two``# to get unique values from list``# importing counter from collections``from` `collections ``import` `Counter` `# Function to get unique values``def` `unique(list1):``  ` `    ``# Print directly by using * symbol``    ``print``(``*``Counter(list1))`  `# driver code``list1 ``=` `[``10``, ``20``, ``10``, ``30``, ``40``, ``40``]``print``(``"the unique values from 1st list is"``)``unique(list1)`  `list2 ``=` `[``1``, ``2``, ``1``, ``1``, ``3``, ``4``, ``3``, ``3``, ``5``]``print``(``"\nthe unique values from 2nd list is"``)``unique(list2)` `# This code is contributed by vikkycirus`

Output:

```the unique values from 1st list is
10 20 30 40

the unique values from 2nd list is
1 2 3 4 5```

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