Python | Find missing elements in List

Sometimes, we can get elements in range as input but some values are missing in otherwise consecutive range. We might have a use case in which we need to get all the missing elements. Let’s discuss certain ways in which this can be done.

Method #1 : Using list comprehension
We can perform the task of finding missing elements using the range function to get the maximum element fill and then insert the elements if there is a miss.

# Python3 code to demonstrate 
# Finding missing elements in List 
# using list comprehension 
  
# initializing list 
test_list = [3, 5, 6, 8, 10] 
  
# printing original list 
print("The original list : " + str(test_list)) 
  
# using list comprehension 
# Finding missing elements in List 
res = [ele for ele in range(max(test_list)+1) if ele not in test_list] 
  
# print result 
print("The list of missing elements : " + str(res)) 

Output :

The original list : [3, 5, 6, 8, 10]
The list of missing elements : [0, 1, 2, 4, 7, 9]

Method #2 : Using set()
This problem can also be performed using the properties of difference of set and then getting the elements that are missing in a range.

# Python3 code to demonstrate 
# Finding missing elements in List 
# Using set() 
  
# initializing list 
test_list = [3, 5, 6, 8, 10] 
  
# printing original list 
print("The original list : " + str(test_list)) 
  
# Using set() 
# Finding missing elements in List 
res = list(set(range(max(test_list) + 1)) - set(test_list)) 
  
# print result 
print("The list of missing elements : " + str(res)) 

Output :

The original list : [3, 5, 6, 8, 10]
The list of missing elements : [0, 1, 2, 4, 7, 9]

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Improved By : Akanksha_Rai