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python-3.xprogram-slicing

Nested List using indexing and slicing

How do I slice or index this list in order to get the answer below? I've tried doing multiple methods of slicing and nothing has worked for me.

L = [0, [], [1,2,3,4], [[5],[6,7]], [8,9,10]]
newL = [L[0],L[2][1],L[2][2],L[3][0]]

Answer: [0, 2, 3, [5 ,6], 8, 10]

newL is what I have so far, but I can't seem to get the [6,7] split in the nested list.

Solution

  • We start with:

    L = [0, [], [1, 2, 3, 4], [[5], [6, 7]], [8, 9, 10]]

    We want:

    [0, 2, 3, [5, 6], 8, 10]

    Let's start from the farthest inside. We need [5, 6]. These are both buried:

    >>> L[3][0][0]
5
>>> L[3][1][0]
6
>>> [L[3][0][0], L[3][1][0]]
[5, 6]

    One layer farther out we need 2, 3:

    >>> L[2][1]
2
>>> L[2][2]
3

    Now put it together:

    >>> [L[0], L[2][1], L[2][2], [L[3][0][0], L[3][1][0]], L[4][0], L[4][2]]
[0, 2, 3, [5, 6], 8, 10]