# Python | Print the common elements in all sublists

• Last Updated : 30 Dec, 2022

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

## Python3

 `# 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)`

Output:

`[40, 30]`

Method #2: Using reduce and map

## Python3

 `# 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)`

Output:

`[40, 30]`

Method #3: Using set.intersection

## Python3

 `# 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)`

Output:

`[40, 30]`

Method #3: Using all()

Another approach to find common elements in all sublists could be using the built-in all function and a list comprehension. Here’s an example of how this could work:

## Python3

 `# Python code to find duplicate element in all``# sublist from list of list``Input` `=` `[ [``10``, ``20``, ``30``, ``40``],``          ``[``30``, ``40``, ``60``, ``70``],``          ``[``20``, ``30``, ``40``, ``60``, ``70``],``          ``[``30``, ``40``, ``80``, ``90``], ]` `common_elements ``=` `[x ``for` `x ``in` `Input``[``0``] ``if` `all``(x ``in` `sublist ``for` `sublist ``in` `Input``)]` `print``(common_elements)``#This code is contributed by Edula Vinay Kumar Reddy`

Output

`[30, 40]`

This will iterate through each element in the first sublist, and check if that element is present in all of the other sublists. If it is, it will be added to the common_elements list. At the end, the common_elements list will contain the elements that are common to all sublists.

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