How to cut an array and reshape it while keeping the content in order?
8 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
Joseph Schmidt
am 5 Jul. 2016
Beantwortet: Jos (10584)
am 6 Jul. 2016
I have an array similar to what's below. How do I cut and move it so that after the 11th column (were it begins to go to 1 again) so that it's a 10x11 matrix instead of 5x22?
The reshape function doesn't work as it keeps the 1st column, pushes the 2nd column down and below the 1st column, keeps the 3rd column, and pushes the 4th column below the 2nd column. It messes up the data. Basically I want to cut the latter half of the data from column 12:end and place it below the 1:11 columns.
(5x22) T1 =
1 1 1 1 1 1 1 1 0 0 0 1 1 1 1 1 1 1 1 0 0 0
1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 1 1 1 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 0
1 1 1 1 1 0 0 0 0 0 0 1 1 1 1 1 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 1 1 0
(10x11)T1 =
1 1 1 1 1 1 1 1 0 0 0
1 1 1 1 1 1 1 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0
1 1 1 1 1 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0
1 1 1 1 1 1 1 1 0 0 0
1 1 1 1 1 1 1 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0
1 1 1 1 1 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0
0 Kommentare
Akzeptierte Antwort
Star Strider
am 5 Jul. 2016
This is how I would do it:
T1 = [T1(:,1:11); T1(:,12:end)]
2 Kommentare
Star Strider
am 5 Jul. 2016
My pleasure.
The easiest way is to use the size function to define the column length.
This works with your ‘T1’ matrix, and should work for the others:
T1 = [T1(:,1:fix(size(T1,2)/2)); T1(:,fix(size(T1,2)/2)+1:end)]
The fix call may not be absolutely necessary, but I always include it to prevent problems.
Weitere Antworten (3)
Stephen23
am 6 Jul. 2016
Bearbeitet: Stephen23
am 6 Jul. 2016
This code can easily be changed to split the matrix into two, three, or more blocks. It assumes that the number of columns is divisible by this number of blocks.
>> blk = 2;
>> tmp = reshape(T1,size(T1,1),[],blk);
>> reshape(permute(tmp,[1,3,2]),[],size(tmp,2))
ans =
1 1 1 1 1 1 1 1 0 0 0
1 1 1 1 1 1 1 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0
1 1 1 1 1 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0
1 1 1 1 1 1 1 1 0 0 0
1 1 1 1 1 1 1 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0
1 1 1 1 1 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 1 0
Example
We first define a function:
function out = moveblock(mat,blk)
tmp = reshape(mat,size(mat,1),[],blk);
out = reshape(permute(tmp,[1,3,2]),[],size(tmp,2));
end
and test this on a matrix:
>> T = ones(3,1)*(1:12)
T =
1 2 3 4 5 6 7 8 9 10 11 12
1 2 3 4 5 6 7 8 9 10 11 12
1 2 3 4 5 6 7 8 9 10 11 12
>> moveblock(T,2)
ans =
1 2 3 4 5 6
1 2 3 4 5 6
1 2 3 4 5 6
7 8 9 10 11 12
7 8 9 10 11 12
7 8 9 10 11 12
>> moveblock(T,3)
ans =
1 2 3 4
1 2 3 4
1 2 3 4
5 6 7 8
5 6 7 8
5 6 7 8
9 10 11 12
9 10 11 12
9 10 11 12
>> moveblock(T,4)
ans =
1 2 3
1 2 3
1 2 3
4 5 6
4 5 6
4 5 6
7 8 9
7 8 9
7 8 9
10 11 12
10 11 12
10 11 12
0 Kommentare
Jos (10584)
am 6 Jul. 2016
This is easy using a cell array as an intermediate step
T = repmat(1:12,3,1) % example array
S = size(T)
n = 3
if mod(S(2),n)>0
C = mat2cell(T, S(1), repmat(S(2)/n,1,n))
Tout = cat(1,C{:})
else
disp('Not possible.')
Tout = []
end
0 Kommentare
Siehe auch
Kategorien
Mehr zu Loops and Conditional Statements finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!