Extract consecutive elements from a vector in a sliding manner

Hi all,

If I have a vector:

A = [1 ;2 ;3 ;4 ;5 ;6];

and I want to extract 2 elements in a way that I should get in each loop:

for i  1:size(A,1)
    A_slice = [?];
end

The answer I'm looking for, for each loop I should get:

%Loop 1: A_slice=[1;2]
%Loop 2: A_slice=[3;4]
%Loop 3: A_slice=[5;6]

any help would be appreicted.

Answer 1

[Matt J]

A = [1 ;2 ;3 ;4 ;5 ;6];
Ar=reshape(A,2,[]);

for i=1:size(Ar,2)
    
    A_slice=Ar(:,i)
    
end

A_slice = 2×1

1 2

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A_slice = 2×1

3 4

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A_slice = 2×1

5 6

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Answer 2

[dpb]

Alternatively, depending upon end use, without the explicit loop can generate the subsets directly...

x=[1:6].';
n=2;
slice=arrayfun(@(i)x(i:i+n-1),1:n:numel(x)-1,'UniformOutput',false)

slice = 1x3 cell array
    {2x1 double}    {2x1 double}    {2x1 double}

or, more succinctly

slice=num2cell(reshape(x,n,[]),1)

slice = 1x3 cell array
    {2x1 double}    {2x1 double}    {2x1 double}

ADDENDUM: I see now that the latter above was already shown by @Matt J, I just recast into the cell array with generic number of elements. Of course, either fails if numel(x) isn't integer multiple of n.

Answer 3

[Walter Roberson]

A = [1 ;2 ;3 ;4 ;5 ;6];
A_slice = buffer(A, 2)

A_slice = 2×3

1 3 5 2 4 6

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now do things with the columns.

buffer() requires the Signal Processing Toolbox. (Personally, I think it ought to be made part of basic MATLAB.)

buffer() has the advantage of smoothly handling the case where the input vector is not an exact multiple of the buffer size.