Reshaping a Char Array

Hi,

I am currently working on a Project where I need to order a Char Array like shown below

A = ['12';'12';'12';'12';'12';'12';'12';'12';'34';'34';'34';'34';'34';'34';'34';'34';'56';'56';'56';'56';'56';'56';'56';'56';'78';'78';'78';'78';'78';'78';'78';'78';'AA';'AA';'AA';'AA';'AA';'AA';'AA';'AA';'BB';'BB';'BB';'BB';'BB';'BB';'BB';'BB';'CC';'CC';'CC';'CC';'CC';'CC';'CC';'CC';'DD';'DD';'DD';'DD';'DD';'DD';'DD';'DD'];

I want to re-arrange the char array like:

'1234'
'1234'
'1234'
'1234'
'1234'
'1234'
'1234'
'1234'
'5678'
'5678'
'5678'
'5678'
'5678'
'5678'
'5678'
'5678'
'AABB'
'AABB'
'AABB'
'AABB'
'AABB'
'AABB'
'AABB'
'AABB'
'CCDD'
'CCDD'
'CCDD'
'CCDD'
'CCDD'
'CCDD'
'CCDD'
'CCDD'

What is the best way to do that? I tried using reshape function but it doesn't seem to work for this case?

Thanks in advance.

Answer 1

[Rik]

This should do it:

A = ['12';'12';'12';'12';'12';'12';'12';'12';'34';'34';'34';'34';'34';'34';'34';'34';'56';'56';'56';'56';'56';'56';'56';'56';'78';'78';'78';'78';'78';'78';'78';'78';'AA';'AA';'AA';'AA';'AA';'AA';'AA';'AA';'BB';'BB';'BB';'BB';'BB';'BB';'BB';'BB';'CC';'CC';'CC';'CC';'CC';'CC';'CC';'CC';'DD';'DD';'DD';'DD';'DD';'DD';'DD';'DD'];
B=mat2cell(A,ones(size(A,1),1),2);
B=reshape(B,8,[]);
part1=B(:,1:2:end);part1=part1(:);
part2=B(:,2:2:end);part2=part2(:);
B=cell2mat([part1 part2]);

[Jack Gallahan]

Also is this the most efficient way to do this?

Because I have 134,217,728 Bytes each is 2 chars converting mat2cell and back takes to much time and memory. Sometimes matlab gives Out of Memory error. Is there another way?

Answer 2

[Ameer Hamza]

Something like this

A = ['12';'12';'12';'12';'12';'12';'12';'12';'34';'34';'34';'34';'34';'34';'34';'34';'56';'56';'56';'56';'56';'56';'56';'56';'78';'78';'78';'78';'78';'78';'78';'78';'AA';'AA';'AA';'AA';'AA';'AA';'AA';'AA';'BB';'BB';'BB';'BB';'BB';'BB';'BB';'BB';'CC';'CC';'CC';'CC';'CC';'CC';'CC';'CC';'DD';'DD';'DD';'DD';'DD';'DD';'DD';'DD'];

idx = find([1; diff(A(:,1))]);
B = reshape(string(A), diff(idx(1:2)), []);
B = B(:,1:2:end) + B(:,2:2:end);
B = char(B(:));

[Rik]

Ah, you must have posted this just before I refreshed the page. Interesting to see a different strategy.

[Ameer Hamza]

Interestingly another question today had a somewhat common structure: https://www.mathworks.com/matlabcentral/answers/615958-how-to-create-arrays-from-repeated-matrix-raws#answer_515683?s_tid=prof_contriblnk, so writing this answer just required a bit of modification.

[Jack Gallahan]

The above numbers was just an example. What if indexes repeated at 256 not 8 like:

A(1)       A(257)
A(2)       A(258)
A(3)       A(259)
.           .
.           .      
.           .
.           .
A(256)     A(512)
A(513)     A(769)
.           .
.           .
.           .
.           .
A(768)     A(1024)

and so on.

[Rik]

Have you seen my answer below? This answer can also be modified for such cases, but mine would have an obvious parameter to edit.

[Ameer Hamza]

It appears to be working in that case too

A = [repmat('12', 256, 1); repmat('34', 256, 1); repmat('56', 256, 1); repmat('78', 256, 1); repmat('AA', 256, 1); repmat('BB', 256, 1); repmat('CC', 256, 1); repmat('DD', 256, 1)];

idx = find([1; diff(A(:,1))]);
B = reshape(string(A), diff(idx(1:2)), []);
B = B(:,1:2:end) + B(:,2:2:end);
B = char(B(:));

The only case it will fail is if the second letter changes and the first letter remain same, for example

A = ['12';'12';'14';'14';'56';'56';'78';'78';'AA';'AA';'BB';'BB';'CC';'CC';'DD';'DD'];

In that case, following modification

idx = find([1; any(diff(A),2)]);

works, which is a more general form of the line in my answer and work for the original input too.

[Jack Gallahan]

The problem is, original data is ADC values which varies continously thus I can not rely on value of first 4 bit and second 4 bit. Values might be '9C', '00','15','0E,'28'..... and so on. The numbers on my first post was just to show the placement of chars that is needed.