In this post, we will learn how to find duplicates from a list in Python with a very simple explanation and algorithms.

It is a very simple task to find duplicates from the list. Basically, we use the `count()` method of the list to count the occurrence of the elements. If the occurrence of the element is greater than one that means it is a duplicate element.

This is how we extract duplicate elements from the list. Let’s see the algorithm first and then write code according to it.

## Algorithm to find duplicates from a list

1. Create an empty set with the name `store_d` to store duplicate elements of the list.
2. Using loop iterate in the list (name of this is`my_list`).
3. Inside the loop check `if my_list.count(i) > 1` then add that element in the empty set (`store_d.add(i)`).
4. Convert the set into the list (`store_d = list(store_d)`).
5. At the end print the list ( `print(store_d)`).

From the algorithm logic and implementation are clear but before writing this program few programming concepts you have to know:

## Source Code

``````my_list = [1,2,2,3,4,5,5,5,6,7]
store_d = set() # instead of list we use set because we want to store every duplicate value only once
for i in my_list:
if my_list.count(i) > 1:

store_d = list(store_d) # convert set into the list

print(f"List : {my_list}")
print(f"Duplicate elements of the list: {store_d}")``````

## Output

``````List : [1, 2, 2, 3, 4, 5, 5, 5, 6, 7]
Duplicate elements of the list: [2, 5]``````

We will also write this program in very few lines of code using list comprehension.

## Find duplicates from a list in Python Using list comprehension

Few programming concepts you have to know before writing this program:

``````my_list = [-1,1,-1,3,4,7,4,9,1,8]
duplicate_l = list(set([i for i in my_list if my_list.count(i)>1]))
print(f"List : {my_list}")
print(f"Duplicate elements of the list: {duplicate_l}") ``````

Output:

``````List : [-1, 1, -1, 3, 4, 7, 4, 9, 1, 8]
Duplicate elements of the list: [1, 4, -1]`````` Hi, I'm Yagyavendra Tiwari, a computer engineer with a strong passion for programming. I'm excited to share my programming knowledge with everyone here and help educate others in this field.