Python | Print the common elements in all sublists

Given a list of lists, the task is to find the elements which are common in all sublist.

There are various approaches to do this task. Let’s discuss the approaches one by one.

Method #1: Using set



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# Python code to find duplicate element in all 
# sublist from list of list
  
# List of list initialization
Input = [ [10, 20, 30, 40],
          [30, 40, 60, 70],
          [20, 30, 40, 60, 70],
          [30, 40, 80, 90], ]
  
Output = set(Input[0])
for l in Input[1:]:
    Output &= set(l)
  
# Converting to list
Output = list(Output)
  
# Printing answer
print(Output)

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Output:

[40, 30]

 
Method #2: Using reduce and map

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# Python code to find duplicate element in all 
# sublist from list of list
import operator
from functools import reduce
  
# List of list initialization
Input = [ [10, 20, 30, 40],
          [30, 40, 60, 70],
          [20, 30, 40, 60, 70], 
          [30, 40, 80, 90], ]
  
# using reduce and map
out = reduce(operator.iand, map(set, Input))
  
# Converting into list
out = list(out)
  
# Printing output
print(out)

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Output:

[40, 30]

 
Method #3: Using set.intersection

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# Python code to find duplicate element in all 
# sublist from list of list
  
# importing reduce 
from functools import reduce
  
# function for set intersection
def func(a, b):
    return list(set(a).intersection(set(b)))
  
# List of list initialization
Input = [ [10, 20, 30, 40],
          [30, 40, 60, 70],
          [20, 30, 40, 60, 70], 
          [30, 40, 80, 90], ]
  
# using reduce and set.intersection
out = reduce(func, Input)
  
# Printing output
print(out)

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Output:

[40, 30]


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