Python | Get duplicate tuples from list

Sometimes, while working with records, we can have a problem of extracting those records which occur more than once. This kind of application can occur in web development domain. Let’s discuss certain ways in which this task can be performed.

Method #1 : Using list comprehension + set() + count()
Initial approach that can be applied is that we can iterate on each tuple and check it’s count in list using count(), if greater than one, we can add to list. To remove multiple additions, we can convert the result to set using set().

# Python3 code to demonstrate working of
# Get duplicate tuples from list
# Using list comprehension + set() + count()

# initialize list
test_list = [(3, 4), (4, 5), (3, 4),
             (3, 4), (4, 5), (6, 7)]

# printing original list
print("The original list : " + str(test_list))

# Get duplicate tuples from list
# Using list comprehension + set() + count()
res = list(set([ele for ele in test_list
            if test_list.count(ele) > 1]))

# printing result
print("All the duplicates from list are : " + str(res))

Output :

The original list : [(3, 4), (4, 5), (3, 4), (3, 4), (4, 5), (6, 7)]
All the duplicates from list are : [(4, 5), (3, 4)]

Method #2 : Using Counter() + items() + list comprehension
The combination of above functions can also be used to perform this particular task. In this, we just get the count of each occurrence of element using Counter() as dictionary and then extract all those whose value is above 1.

# Python3 code to demonstrate working of
# Get duplicate tuples from list
# Using list comprehension + Counter() + items()
from collections import Counter

# initialize list
test_list = [(3, 4), (4, 5), (3, 4),
             (3, 4), (4, 5), (6, 7)]

# printing original list
print("The original list : " + str(test_list))

# Get duplicate tuples from list
# Using list comprehension + Counter() + items()
res = [ele for ele, count in Counter(test_list).items()
                                          if count > 1]

# printing result
print("All the duplicates from list are : " + str(res))

Output :

The original list : [(3, 4), (4, 5), (3, 4), (3, 4), (4, 5), (6, 7)]
All the duplicates from list are : [(4, 5), (3, 4)]