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Python | Consecutive elements grouping in list
• Last Updated : 09 Sep, 2019

Sometimes, while working with Python lists, we can have a problem in which we might need to group the list elements on basis of their respective consecutiveness. This kind of problem can occur while data handling. Let’s discuss certain way in which this task can be performed.

Method : Using `enumerate() + groupby()` + generator function + lambda
This task can be performed using the combination of above functions. In this, we create a generator function, in which we pass the list whose index-element are accessed using `enumerate()` and grouped by consecutive elements using `groupby()` and lambda. Works with Python2 only

 `# Python code to demonstrate working of``# Consecutive elements grouping list``# using enumerate() + groupby() + generator function + lambda``import` `itertools`` ` `# Utility Generator Function``def` `groupc(test_list):``    ``for` `x, y ``in` `itertools.groupby(``enumerate``(test_list), ``lambda` `(a, b): b ``-` `a):``        ``y ``=` `list``(y)``        ``yield` `y[``0``][``1``], y[``-``1``][``1``]`` ` `# initialize list``test_list ``=` `[``1``, ``2``, ``3``, ``6``, ``7``, ``8``, ``11``, ``12``, ``13``]`` ` `# printing original list``print``(``"The original list is : "` `+` `str``(test_list))`` ` `# Consecutive elements grouping list``# using enumerate() + groupby() + generator function + lambda``res ``=` `list``(groupc(test_list))`` ` `# printing result``print``(``"Grouped list is : "` `+` `str``(res))`
Output :
```The original list is : [1, 2, 3, 6, 7, 8, 11, 12, 13]
Grouped list is : [(1, 3), (6, 8), (11, 13)]
```

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