Creating a array of 1s and 0s using another array

Question

So I have two arrays (row and column) row = [0, 1, 0, 2, 0, 1, 3, 1, 3, 1, 2, 4] and column = [0, 0, 1, 1, 2, 2, 2, 3, 3, 0, 1, 4]

I want to use the rows and columns arrays to insert the value "1" into another 2D array (vectors)

vectors = 
[[0. 0. 0. 0. 0.],
[0. 0. 0. 0. 0.],
[0. 0. 0. 0. 0.],
[0. 0. 0. 0. 0.],
[0. 0. 0. 0. 0.]]

so my desired output is:

vectors = 
[[1. 1. 1. 0. 0.],
[1. 0. 1. 1. 0.],
[0. 1. 0. 0. 0.],
[0. 0. 1. 1. 0.],
[0. 0. 0. 0. 1.]]

Sorry if my explanation is bad it's my first time using python and Stackoverflow.

@Epsi95 I am creating a vector from those values so I need to use the rows and columns to show the position where to add the 1's. — zsoq
– zsoq, Commented Mar 6, 2021 at 19:58

Sayandip Dutta · Accepted Answer · 2021-03-06 16:03:29Z

2

Just use the row and column vector as indices:

>>> vectors[row, column] = 1
>>> vectors
array([[1., 1., 1., 0., 0.],
       [1., 0., 1., 1., 0.],
       [0., 1., 0., 0., 0.],
       [0., 0., 1., 1., 0.],
       [0., 0., 0., 0., 1.]])

answered Mar 6, 2021 at 16:03

Sayandip Dutta

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1 Comment

zsoq Over a year ago

Oh wow, it was that simple thanks for the help; I need to work on my python skills.

Mark M · Accepted Answer · 2021-03-06 16:03:17Z

2

I think you could try this:

for r, c in zip(row, column):
    vectors[r][c] = 1

answered Mar 6, 2021 at 16:03

Mark M

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1 Comment

Mark M Over a year ago

no problem! Actually, I learned a little something from @Cyttorak's answer, too, so that's a bonus.

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