How to sequentially generate a vector from loop?

Hi everyone!

I have a vector A, which I cut in a loop and take the first elements like this

A = [ 1 2 3 4 5 6 7]'

for k=1:7
A_{k} = A(1:k)
end

I want to generate a vector B which can put a subset of A (let's say the first 2 elements (A_{2}')) together with the last element of every generated vector from my loop. Basically B should be like this

B = [A_{2}' A_{3}(3) A_{4}(4) A_{5}(5) A_{6}(6) A_{7}(7)]'

How can I make this vector B easier to write for bigger k's (for example write it like a loop) ?

Thank you so much!

[Dyuman Joshi]

B is same as A. Simply assign it directly.

A = [ 1 2 3 4 5 6 7]'

A = 7×1

1 2 3 4 5 6 7

for k=1:7
A_{k} = A(1:k);
end
B = [A_{2}' A_{3}(3) A_{4}(4) A_{5}(5) A_{6}(6) A_{7}(7)]'

B = 7×1

1 2 3 4 5 6 7

[Ani Asoyan]

With this loop it's same, but if there's another function in the loop, it's not the same. I just want to create a vector B, which contains first 2 elements of A and every time it adds the last element of a for loop

[Dyuman Joshi]

"but if there's another function in the loop"

For example?

"I just want to create a vector B, which contains first 2 elements of A and every time it adds the last element of a for loop"

Give another example, as it is not clear from the one you gave.

Answer 1

[Sargondjani]

It's not clear what exaclty is your problem. But maybe something like this can help you:

s=2

for k=1:7
A_{k} = A(1:k);

if k==s
    B = [A_{2}']
    
elseif k>s
     B = [B' A_{k}(k)]'
    
end
end

Try to get the details right yourself.