We can count backwards to flip a matrix A upside down with
sage: A[::-1,:]=A; A
Can we do it from left to right; I mean, for the matrix A=
[ 3 2 -5 0]
[ 1 -1 1 -4]
[ 1 0 1 -3]
Is there an easy way to obtain the following matrix
[ 0 -5 2 3]
[-4 1 -1 1]
[ 3 1 0 1]
Well, you could use the matrix_from_columns method:
sage: A = matrix(3, 3, range(9))
sage: A
[0 1 2]
[3 4 5]
[6 7 8]
sage: A.matrix_from_columns(range(2,-1,-1))
[2 1 0]
[5 4 3]
[8 7 6]
Or you could take the transpose, use your idea to flip upside down, and then take another transpose:
sage: A.transpose()[::-1,:].transpose()
[2 1 0]
[5 4 3]
[8 7 6]
You're almost there!
sage: a = matrix(3, 3, range(9))
sage: b = a[::-1,:] # reverse lines
sage: c = a[:,::-1] # reverse columns
sage: d = a[::-1,::-1] # reverse both
sage: a, b, c, d
(
[0 1 2] [6 7 8] [2 1 0] [8 7 6]
[3 4 5] [3 4 5] [5 4 3] [5 4 3]
[6 7 8], [0 1 2], [8 7 6], [2 1 0]
)
Asked: 2015-02-24 15:30:07 +0100
Seen: 1,584 times
Last updated: Feb 25 '15
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