Sorting matrices in matlab
显示 更早的评论
Hello,
I have a NxM matrix:
Random A for example 10x5
A =
2 8 7 1 4
9 8 8 1 7
4 8 2 8 8
3 3 2 10 6
8 7 6 7 8
1 6 5 2 3
1 4 9 8 8
7 1 8 2 10
7 8 8 2 9
6 4 1 7 1
I would like to make another matrix (B) that contains first every N, N+2, N+4...and after them N+1,N+3.. ect
B =
2 8 7 1 4
4 8 2 8 8
8 7 6 7 8
1 4 9 8 8
7 8 8 2 9
9 8 8 1 7
3 3 2 10 6
1 6 5 2 3
7 1 8 2 10
6 4 1 7 1
Thank you.
1 个评论
Stephen23
2018-7-5
Note that this is a topic of indexing/rearranging the elements, where the element values are not relevant to the new order (only their indices are). Sorting depends only on the element values (not their indices).
采纳的回答
Stephen23
2018-7-5
>> B = A([1:2:end,2:2:end],:)
B =
2 8 7 1 4
4 8 2 8 8
8 7 6 7 8
1 4 9 8 8
7 8 8 2 9
9 8 8 1 7
3 3 2 10 6
1 6 5 2 3
7 1 8 2 10
6 4 1 7 1
4 个评论
Matija Kosak
2018-7-5
@Matija Kosak: I would use reshape and permute to generalize this (note that the number of rows N has to be exactly divisible by R):
>> A = randi(99,12,5) % size NxM
A =
35 89 14 49 65
76 33 18 98 14
29 59 53 29 54
63 69 51 27 50
21 96 86 17 55
60 14 56 30 54
40 16 17 43 60
62 73 78 80 3
37 31 23 84 54
8 17 26 72 29
62 54 55 46 2
31 67 1 99 29
>> R = 4; % N must be divisible by R.
>> S = size(A);
>> B = reshape(permute(reshape(A,R,[],S(2)),[2,1,3]),S)
B =
35 89 14 49 65
21 96 86 17 55
37 31 23 84 54
76 33 18 98 14
60 14 56 30 54
8 17 26 72 29
29 59 53 29 54
40 16 17 43 60
62 54 55 46 2
63 69 51 27 50
62 73 78 80 3
31 67 1 99 29
>> C = A([1:4:end,2:4:end,3:4:end,4:4:end],:) % needs to match this!
C =
35 89 14 49 65
21 96 86 17 55
37 31 23 84 54
76 33 18 98 14
60 14 56 30 54
8 17 26 72 29
29 59 53 29 54
40 16 17 43 60
62 54 55 46 2
63 69 51 27 50
62 73 78 80 3
31 67 1 99 29
>> isequal(B,C)
ans = 1
Matija Kosak
2018-7-5
Matija Kosak
2018-7-5
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Shifting and Sorting Matrices 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
