How can I copy items from a nested list to more than one list

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I have a nested list called inputs. Let's assume that it is like so

inputs = [[1,0,1],[0,0,1]]

Now I added 3 empty lists (row_1,row_2,row_3) they should be appended by the respectful index in a list in the nested list. For further explanation:

#They should be like this
row_1 = [1,0]
row_2 = [0,0]
row_3 = [1,1]

What I have tried:

Python

row_1 = []
row_2 = []
row_3 = []
for lists in inputs:
    for index in lists:
        row_1.append(inputs[index - 1][0])
        row_2.append(inputs[index - 1][1])
        row_3.append(inputs[index - 1][2])

Which resulted in:

row_1 = [1,0,1,1,1,1]
row_2 = [0,0,0,0,0,0]
row_3 = [1,1,1,1,1,1]

I suspect that the problem is in the for loop. Can it be solved with a while loop?

Posted 27-Nov-21 8:02am

Eyad Mohamed

Updated 27-Nov-21 9:05am

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Patrice T · Accepted Answer · 2021-11-27T09:05:00

I would try something like

Python

row_1 = []
row_2 = []
row_3 = []
for lists in inputs:
    for index in lists:
        row_1.append(inputs[index - 1][0])
        row_2.append(inputs[index - 1][1])
        row_3.append(inputs[index - 1][2])
    row_1.append(lists[0])
    row_2.append(lists[1])
    row_3.append(lists[2])

Your code do not behave the way you expect, or you don't understand why !

There is an almost universal solution: Run your code on debugger step by step, inspect variables.
The debugger is here to show you what your code is doing and your task is to compare with what it should do.
There is no magic in the debugger, it don't know what your code is supposed to do, it don't find bugs, it just help you to by showing you what is going on. When the code don't do what is expected, you are close to a bug.
To see what your code is doing: Just set a breakpoint and see your code performing, the debugger allow you to execute lines 1 by 1 and to inspect variables as it execute.

Debugger - Wikipedia, the free encyclopedia[^]

Mastering Debugging in Visual Studio 2010 - A Beginner's Guide[^]
Basic Debugging with Visual Studio 2010 - YouTube[^]

27.3. pdb — The Python Debugger — Python 3.6.1 documentation[^]
Debugging in Python | Python Conquers The Universe[^]
pdb – Interactive Debugger - Python Module of the Week[^]

The debugger is here to only show you what your code is doing and your task is to compare with what it should do.