🔒 Reverse individual rows in matrix in place without reversing entire matrix

[turbid cloak]

In a 2d matrix, I want to reverse each row in matrix without changing order of rows.

example: I have a matrix [[1,2,3], [4,5,6], [7,8,9]]
If i use python reverse function, it becomes [[9,8,7], [6,5,4], [3,2,1]]
Instead my desired result is [[3,2,1], [6,5,4], [9,8,7]]

We can use small code snippet like

     row.reverse()

But is there a way to incorporate this in reverse function only? Sorry if this is a dumb question, i am not very good with programming

[loud cargo]

@turbid cloak

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[austere hawk]

You might be interested to look at Numpy.

Otherwise, addressing each row object and calling each's reverse method might be the best approach, as you've done.

!e py import numpy as np arr = np.arange(1, 10).reshape(3, 3) print(arr) arr = arr[:, ::-1] print(arr)

[loud cargo]

:white_check_mark: Your 3.12 eval job has completed with return code 0.

001 | [[1 2 3]
002 |  [4 5 6]
003 |  [7 8 9]]
004 | [[3 2 1]
005 |  [6 5 4]
006 |  [9 8 7]]

[turbid cloak]

Is it inplace though? Cause according to my understanding arr[:,::-1] will create a new copy. But i don't know about numpy

[austere hawk]

It can be.

!e py import numpy as np arr = np.arange(1, 10).reshape(3, 3) print(arr, id(arr)) arr[:] = arr[:, ::-1] print(arr, id(arr))

[loud cargo]

:white_check_mark: Your 3.12 eval job has completed with return code 0.

001 | [[1 2 3]
002 |  [4 5 6]
003 |  [7 8 9]] 139927938524400
004 | [[3 2 1]
005 |  [6 5 4]
006 |  [9 8 7]] 139927938524400

[austere hawk]

There's probably some named method, even. I'll just check.

[turbid cloak]

reversed will return a new copy too i guess

reverse is the best way so far

[austere hawk]

!e py import numpy as np arr = np.arange(1, 10).reshape(3, 3) arr[:] = np.flip(arr, 1) print(arr)

[loud cargo]

:white_check_mark: Your 3.12 eval job has completed with return code 0.

001 | [[3 2 1]
002 |  [6 5 4]
003 |  [9 8 7]]

[loud cargo]

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