# Python – Dual element Rows Combinations

Sometimes, while working with data, we can have a problem in which we need to find combinations in list. This can be a simple. But sometimes, we need to perform a variation of it and have a dual element row instead of a single element. Let’s discuss certain ways in which this task can be performed.

Method #1 : Using list comprehension + `enumerate()`
The combination of above functions can be used to perform this task. In this, we iterate through the list and perform the combinations using comprehension and enumerate().

 `# Python3 code to demonstrate  ` `# Dual element Rows Combinations ` `# using list comprehension + enumerate() ` `from` `collections ``import` `defaultdict ` ` `  `# Initializing list ` `test_list ``=` `[[``3``, ``4``], [``5``, ``6``], [``7``, ``8``]] ` ` `  `# printing original list  ` `print``(``"The original list is : "` `+` `str``(test_list)) ` ` `  `# Dual element Rows Combinations ` `# using list comprehension + enumerate() ` `res ``=` `[test_list[idx ``-` `len``(test_list)] ``+` `test_list[idx ``+` `1` `-` `len``(test_list)]  ` `      ``for` `idx, ele ``in` `enumerate``(test_list)] ` ` `  `# printing result  ` `print` `(``"Combination of dual rows list is : "` `+` `str``(res)) `

Output :

```The original list is : [[3, 4], [5, 6], [7, 8]]
Combination of dual rows list is : [[3, 4, 5, 6], [5, 6, 7, 8], [7, 8, 3, 4]]
```

Method #2 : Using` map() + lambda + combinations()`
The combinations of above functions can be used to perform this task. In this, the task of iteration and pairing is done by map() and combinations() respectively.

 `# Python3 code to demonstrate  ` `# Dual element Rows Combinations ` `# using map() + lambda + combinations() ` `from` `itertools ``import` `combinations ` ` `  `# Initializing list ` `test_list ``=` `[[``3``, ``4``], [``5``, ``6``], [``7``, ``8``]] ` ` `  `# printing original list  ` `print``(``"The original list is : "` `+` `str``(test_list)) ` ` `  `# Dual element Rows Combinations ` `# using map() + lambda + combinations() ` `res ``=` `list``(``map``(``lambda` `ele: ele[``0``] ``+` `ele[``1``], combinations(test_list, ``2``))) ` ` `  `# printing result  ` `print` `(``"Combination of dual rows list is : "` `+` `str``(res)) `

Output :

```The original list is : [[3, 4], [5, 6], [7, 8]]
Combination of dual rows list is : [[3, 4, 5, 6], [5, 6, 7, 8], [7, 8, 3, 4]]
```

My Personal Notes arrow_drop_up Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.

Article Tags :

Be the First to upvote.

Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.