Efficiently Extract Vector from MATLAB Matrices

[omri3012]

Hallo,

I have a 3*3 matrices in matlab:

A=[ 1 2 3; 4 5 6; 7 8 9];

and i won't to accept a vector from each colume in an easy way, i.e.

a1=1 2 3 , a2=4 5 6 , a3=7 8 9
so i tried to wrote:

for i=1:3
a_i=A(:,i);
end

but i only the last vector, a3=7 8 9...

if anyone have a good suggestion it would be very helpful.

thnks
Omri

 

[shoehorn]

Hallo,

I have a 3*3 matrices in matlab:

A=[ 1 2 3; 4 5 6; 7 8 9];

and i won't to accept a vector from each colume in an easy way, i.e.

a1=1 2 3 , a2=4 5 6 , a3=7 8 9
so i tried to wrote:

for i=1:3
a_i=A(:,i);
end

but i only the last vector, a3=7 8 9...

if anyone have a good suggestion it would be very helpful.

thnks
Omri

Your problem is with the for loop not doing what you think it's doing. When you say

for i = 1:3
    a_i = A(:, i);
end

you are not declaring three separate vectors a_1, a_2, a_3 and assigning them the rows of A. What you are doing is declaring a vector a_i and successively redefining it to be equal to each row of A, so that by the end of the for loop you have a_i = A(3,:). In other words, simply putting '_i' at the end of a vector isn't how you subscript vectors within Matlab.

 

[omri3012]

thanks for ypur responde,

i understand what you are saying, but is there a loop or other command
that generate 3 vectors a_1, a_2, a_3 from the matrices A?

 

[MRFMengineer]

See this thread:
https://www.physicsforums.com/showthread.php?t=217012

Any reason why you are breaking into vectors instead of leaving it in a matrix?