Python | Combine two lists by maintaining duplicates in first list

Given two lists, the task is to combine two lists and removing duplicates, without removing duplicates in original list.

Example:

Input : 
list_1 = [11, 22, 22, 15]
list_2 = [22, 15, 77, 9]

Output :
OutList = [11, 22, 22, 15, 77, 9]

Code #1: using extend

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# Python code to combine two lists
# and removing duplicates, without
# removing duplicates in original list.
  
# Initialisation of first list
list1 = [111, 222, 222, 115]
  
# Initialisation of Second list
list2 = [222, 115, 77, 19]
  
output = list(list1)
  
# Using extend function
output.extend(y for y in list2 if y not in output)
  
# printing result
print(output)

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Output:


[111, 222, 222, 115, 77, 19]





 

Code #2 : Using Set and Iteration

Append those element in first list which are not in second list and then take union of first and second list.











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# Python code to combine two lists  


# and removing duplicates, without  


# removing duplicates in original list. 


  


# Initialisation of first list 


list1 = [11, 22, 22, 15] 


  


# Initialisation of Second list 


list2 = [22, 15, 77, 9] 


  


# creating set 


unique_list1 = set(list1) 


unique_list2 = set(list2) 


  


# Difference in two sets 


diff_element = unique_list2 - unique_list1 


  


# union of difference + first list 


output = list1 + list(diff_element) 


  


# printing output 


print(output)  



















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Output:


[11, 22, 22, 15, 9, 77]






          
          
          
          

            

    

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