Is there something like 'array colon'? in other words how can I apply colon operator to all the elements of an array (please read the text below so my question will make sense)?

A = [1 10 16 23];

A-3:A+2 will result in [-2,-1,0,1,2,3]; In other words colon operates only on the first element of array A. However I want to apply A-3:A+2 on all the elements of A; I know I can get this by a loop, like :

u=[];for i=1:4, u=[u,A(i)-3:A(i)+2]; end

However I wonder if there is a way to do this without using loop. (The actual array I am working with is too long to loop through it.)

This sounds like a super simple question but I have no ides how to do it in a simple way (other than looping).

I so much appreciate any help.

Answer 1

[Matt Fig]

A = [1 10 16 23];
u = reshape(bsxfun(@plus,A,(-3:2).'),1,[])

[Farzaneh]

superb!!! thank you!

Answer 2

[Azzi Abdelmalek]

do you mean a division

A = [1 10 15 23]; 
(A-3)./(A+2 )

[Farzaneh]

Thanks however I don't want to divide anything ... I want A-3 : A+2

Does that make sense?

[Azzi Abdelmalek]

what does that mean? expected result?

[Azzi Abdelmalek]

I'm not sur what you need

A = [1 10 15 23]; 
unique(cell2mat(arrayfun(@(x)  x-3:x+2,A,'un',0)))

[Farzaneh]

thanks.

Answer 3

[Jan]

Have you seen Bruno's http://www.mathworks.com/matlabcentral/fileexchange/29854-multiple-colon?

[Farzaneh]

When I use mcolon , it gives me this error:

Undefined function 'getclassidmex' for input arguments of type 'double'.

Error in castarrays (line 16) id = getclassidmex(varargout{:}); % get id from 1-12, ordered like numclass

Error in mcolon (line 50) [i1,d,i2] = castarrays(i1(:),d(:),i2(:));

[Matt Fig]

MCOLON is a mex function that must be compiled. You don't need MCOLON to do what you want to do here anyway. See my solution.

Answer 4

[Chris A]

Here is one way to do this:

A = [1 10 16 23];
res=reshape(repmat((-3:2)',1,numel(A))+repmat(A,6,1),[],1);

[Farzaneh]

Thanks. It is similar to what Matt Fig suggested. however he suggested bsxfun which makes things easier than using repmat...