# How to get a unique value from a list in python

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## How to get a unique value from a list in python

1. How to solve How to get a unique value from a list in python

Count the items, keep only those which have a count of 1:
`>>> data = ['a','a','b','a'] >>> from collections import Counter >>> [k for k,v in Counter(data).items() if v == 1] ['b']`

2. How to get a unique value from a list in python

Count the items, keep only those which have a count of 1:
`>>> data = ['a','a','b','a'] >>> from collections import Counter >>> [k for k,v in Counter(data).items() if v == 1] ['b']`

## Solution 1

Count the items, keep only those which have a count of 1:

``````>>> data = ['a','a','b','a']
>>> from collections import Counter
>>> [k for k,v in Counter(data).items() if v == 1]
['b']
``````

Original Author juanpa.arrivillaga Of This Content

## Solution 2

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.

Example to make a unique function :

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

You can also use numpy.unique example:

`
#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 should be :
the unique values from 1st list is
[10 20 30 40]

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

Original Author Saso Of This Content

## Solution 3

You could use `collections.Counter()` for this, e.g.:

``````from collections import Counter

my_list = ['a','a','b','a']

counts = Counter(my_list)

for element, count in counts.items():
if count == 1:
print(element)
``````

would print `b` and nothing else in this case.

Or, if you’d like to store the result in a list:

``````from collections import Counter

my_list = ['a','a','b','a']

counts = Counter(my_list)

unique_elements = [element for element, count in counts.items() if count == 1]
``````

`unique_elements` is `['b']` in this case.

Original Author Paul P Of This Content

## Solution 4

1. Count the appearance of an element in the list, and store it in a dictionary
2. From the dictionary, check which elements has only one appearance
3. Store the unique (one appearance) elements in a list
4. Print the list

You can try this:

``````my_list = ['a','a','b','a']
my_dict = {}
only_one = []

#Step 1
for element in my_list:
if element not in my_dict:
my_dict[element] = 1
else:
my_dict[element] += 1

#Step 2 and Step 3
for key, value in my_dict.items():
if value == 1:
only_one.append(key)

#Step 4
for unique in only_one:
print(unique)
``````

Output:

``````b
``````

In case you are wondering what other variables contain:

``````my_dict = {'a': 3, 'b': 1}
only_one = ['b']
``````

Original Author Its Fragilis Of This Content

## Conclusion

So This is all About This Tutorial. Hope This Tutorial Helped You. Thank You. 