On Saturday, 22 July 2017 at 20:55:06 UTC, kerdemdemir wrote:
We have awesome way for creating slices like:
a = new int[5];
int[] b = a[0..2];
But what about if I have 2D array and I don't want to go
vertical. Something like :
int[3][3] matrix = [
[ 1, 2, 3 ],
[ 4, 5, 6 ],
[ 7, 8, 9 ]
];
I believe I can use std.range function "RoundRobin"(or maybe it
won't work with 2D array directly) for having a good looking
vertical slice which will have 1,4,7 or 2,5,8 or 3,6,9 in my
example above.
And what if I want to go diagonal like 1,5,9 or 3,5,7 in the
example above. Is there a good solution in std without using
for loops?
I have one more requirement for fulfilling the task that I
working on. This slices do not have to be the same size as the
array. For example in the example above slice size could have 2
instead of 3. In this case I need to have slices like
1,5;2,6;4,8;5,9 ... and so on for diagonal case.
Erdem
Ps: Converting the 2D array to 1D array is possible in my case.
Hello Erdem,
You may want to use mir-algorithm DUB package. It is a D tensor
library.
https://github.com/libmir/mir-algorithm
import mir.ndslice;
auto slice = matrix[0].ptr.sliced(3, 3);
auto row = matrix[0];
auto col = matrix[0 .. $, 0];
A lot of examples with diagonal and sub-diagonals can be found
here
http://docs.algorithm.dlang.io/latest/mir_ndslice_topology.html#.diagonal
Best,
Ilya
