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# Python – Extract Even elements in Nested Mixed Tuple

• Last Updated : 24 Feb, 2023

Sometimes, while working with Python tuples, we can have a problem in which we need to get all the even elements from the tuple. The tuples can be nested or mixed. This kind of problem can occur in data domains. Let’s discuss certain ways in which this task can be performed.

Input : test_tuple = (5, (7, 6, (2, (4, ))))
Output : ((6, (2, (4, ))), )

Input : test_tuple = (5, (8, 6, (2, (4, 8))))
Output : ((8, 6, (2, (4, 8))), )

Method #1 : Using recursion + isinstance() + loop
This is one of the ways in which this task can be performed. In this, we perform the task of getting the element instance to be integer using isinstance(), and the function is recursed once tuple is encountered.

## Python3

 `# Python3 code to demonstrate working of``# Extract Even elements in Nested Mixed Tuple``# Using recursion + isinstance() + loop` `# helper_fnc``def` `even_ele(test_tuple, even_fnc):``    ``res ``=` `tuple``()``    ``for` `ele ``in` `test_tuple:``        ``if` `isinstance``(ele, ``tuple``):``            ``res ``+``=` `(even_ele(ele, even_fnc), )``        ``elif` `even_fnc(ele):``            ``res ``+``=` `(ele, )``    ``return` `res` `# initializing tuples``test_tuple ``=` `(``4``, ``5``, (``7``, ``6``, (``2``, ``4``)), ``6``, ``8``)` `# printing original tuple``print``(``"The original tuple : "` `+` `str``(test_tuple))` `# Extract Even elements in Nested Mixed Tuple``# Using recursion + isinstance() + loop``res ``=` `even_ele(test_tuple, ``lambda` `x: x ``%` `2` `=``=` `0``)` `# printing result``print``(``"Even elements of tuple : "` `+` `str``(res))`

Output :

```The original tuple : (4, 5, (7, 6, (2, 4)), 6, 8)
Even elements of tuple : (4, (6, (2, 4)), 6, 8)```

Method #2 : Using recursion + isinstance() + generator expression
This method performs this task in a similar manner as the above method. The difference is just that it is shorthand to the above method, does the job in one line using generator expression.

## Python3

 `# Python3 code to demonstrate working of``# Extract Even elements in Nested Mixed Tuple``# Using recursion + isinstance() + generator expression` `# helper_fnc``def` `even_ele(test_tuple, even_fnc):``    ``return` `tuple``(even_ele(ele, even_fnc) ``if` `isinstance``(ele, ``tuple``) ``else` `ele``    ``for` `ele ``in` `test_tuple ``if` `isinstance``(ele, ``tuple``) ``or` `even_fnc(ele))` `# initializing tuples``test_tuple ``=` `(``4``, ``5``, (``7``, ``6``, (``2``, ``4``)), ``6``, ``8``)` `# printing original tuple``print``(``"The original tuple : "` `+` `str``(test_tuple))` `# Extract Even elements in Nested Mixed Tuple``# Using recursion + isinstance() + generator expression``res ``=` `even_ele(test_tuple, ``lambda` `x: x ``%` `2` `=``=` `0``)` `# printing result``print``(``"Even elements of tuple : "` `+` `str``(res))`

Output :

```The original tuple : (4, 5, (7, 6, (2, 4)), 6, 8)
Even elements of tuple : (4, (6, (2, 4)), 6, 8)```

Method #3: Using for loop

Here’s a step-by-step algorithm

1. Create an empty list called result to hold the even integers found in the tuple.
2. For each element item in the input tuple t:
a. If item is a tuple, recursively call the extract_even_elements function with item as input.
b. If item is an even integer, append it to the result list.
3. Return the result list as a tuple

## Python3

 `def` `extract_even_elements(t):``    ``result ``=` `[]``    ``for` `item ``in` `t:``        ``if` `isinstance``(item, ``tuple``):``            ``result.append(extract_even_elements(item))``        ``elif` `isinstance``(item, ``int``) ``and` `item ``%` `2` `=``=` `0``:``            ``result.append(item)``    ``return` `tuple``(result)` `# Example usage``test_tuple ``=` `(``4``, ``5``, (``7``, ``6``, (``2``, ``4``)), ``6``, ``8``)``result ``=` `extract_even_elements(test_tuple)``# printing original tuple``print``(``"The original tuple : "` `+` `str``(test_tuple))``print``(``"Even elements of tuple : "` `+` `str``(result))``#This code is contributed by Vinay Pinjala.`

Output

```The original tuple : (4, 5, (7, 6, (2, 4)), 6, 8)
Even elements of tuple : (4, (6, (2, 4)), 6, 8)```

Time Complexity: O(n)

Auxiliary Space: O(n)

The time complexity of this function depends on the size of the input tuple and the number of nested tuples. In the worst case, the function would need to traverse every element of the input tuple and any nested tuples, so the time complexity is O(n), where n is the total number of elements in the input tuple.

The space complexity of this function depends on the depth and structure of the nested tuples in the input. At each level of recursion, a new list is created to hold the even integers found within that level of the tuple, and the function continues to call itself until it reaches the end of the nested tuple structure. Therefore, the space complexity is also O(n), where n is the total number of elements in the input tuple.

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