Print or display a group of numbers contained in a vector with loops

Hi everyone,

I arranged a vector of 15 elements in total and I am asked to print the numbers in groups of 3.

a=[2 4 3 5 9 8 2 1 0 2 3 4 7 8 9];

For example, the first print would only print the first three numbers in that vector, then print the next three numbers again, and so on. Let's say: 2 4 3, then 5 9 8 and so on. Of course, I do understand I need to loop my program so it can print five groups (15 elements/3).

Maybe I don't have much experience and my logic understands the following code:

cont=1;
for i=1:length(a)/5
    disp(a(cont))
    cont=cont+3;
end

     2

     5

     2

I failed since it's only printing the numeric value every three results (2 5 2 2 7) and it doesn't print the groups of numbers. I know that this should be done with a single for but I don't understand how I can organize the information.

Answer 1

[KSSV]

REad about reshape

a = [2 4 3 5 9 8 2 1 0 2 3 4 7 8 9];
b = reshape(a,3,[])'

B = 5×3

2 4 3 5 9 8 2 1 0 2 3 4 7 8 9

[Nat]

Hey KSSV,

reshape is a powerful Matlab tool but in fact, we need to emulate that function. I tried again with:

a=[2 4 3 5 9 8 2 1 0 2 3 4 7 8 9];
cont=1;
for i=1:length(a)/5
    disp(a(cont):length(a)/5)
    cont=cont+3;
end

But it is only printing

2 3 4 %It prints this same results 5 times

Of course, it is not printing my group of numbers since I'm looking for the next 5 lines as resulted with the reshape function:

2 4 3 %This is the correct result
5 9 8
2 1 0
2 3 4
7 8 9

[KSSV]

a = [2 4 3 5 9 8 2 1 0 2 3 4 7 8 9];
idx = 0:3:length(a) ;
for i = 2:length(idx)
    a(idx(i-1)+1:idx(i))
end

ans = 1×3

2 4 3

ans = 1×3

5 9 8

ans = 1×3

2 1 0

ans = 1×3

2 3 4

ans = 1×3

7 8 9

[Nat]

Didn't tried creating a new variable with the length measurement so indexing appeared first in an index expression and that's incorrect.

It works! People can print all results separately with

a(idx(i-1)+1:idx(i)) 

Or just one result with 'display'.

disp(a(idx(i-1)+1:idx(i))) 

I really appreciate your willingness. Thank you.