how to plot only one iteration in for loop?

A=[2 2 2; 3 3 3; 1 1 1];

B=[1 2 3];

As you can see it bellow, this loop consist of 3 iterations. Can i ask Matlab to plot the second case or third case only? if its possible, please tell me how?

for i = 1:3

C = B + A(1:end,i)
end
C1 =       
   3
   5
   4
C2 =3
   5
   4
C3 =3
   5
   4

plot (x,C2)

or

plot (x,C3)

Thank you guys for your help, I appreciate any help from you

[Muruganandham Subramanian]

plot b/w what?. Form your question clearly...

[Brwa]

I have edited the question, i hope its been clear enough to understand

Answer 1

[David Sanchez]

for i = 1:3
  C = B + A(1:end,i);
  if i==2
    disp(C);
  end
end

[Brwa]

Hi Mr David thanks for your help again, but what if i have a big loop such as

for i =1:100

is there a better way to do it?

[Image Analyst]

That is not a big loop. Now if you get into the tens of millions of iterations, then you're getting big, but 100 is far, far from a "big loop" so don't worry about it. There is an unjust fear of loops going around. For example, look at this loop where I iterate a million times:

tic;
count = 0;
for k = 1 : 1000000
  count = count + 1;
end
toc

Now look at the elapsed time:

Elapsed time is 0.0071 seconds.

Answer 2

[Muruganandham Subramanian]

what is x?..see while plotting the size of xlabel and ylabel should be same.. In ur code x might be

x=[1 2 3];

If its right, then you can do it by

for i = 1:3
  C = B + A(1:end,i);
  if i~=1
    plot(x,C);
  end
end

[Brwa]

Dear Muruganandham Subramanian you are right, your code is very simple and almost the same as David Sanchez's code, but my problem is, i only know what i want to plot after the end of loop or after i know the result of all C1, C2, Cn.

After knowing the result probabily i will be interested to plot C2 or C3 it depend on the result.

so if x = [ 1 2 3]

for i = 1:3

C = B + A(1:end,i);
end

Ans

C1

C2

C3

now i can decide which one i should plot.

maybe i want to plot (x,C2)

Note C1 not equal C2 not equal C3, in my real code, I just dont put my real code because its too long its consist of several M.files

Thanks brother, Thanks to all of you. I really dont know how to appreciate your helps and your kindness. i hope someday i can help people with my knowledge too.

Answer 3

[Andrei Bobrov]

id = [4 10 26 78]; % Let id case's use for the plotting.

for i1 = 1:100
  C = B + A(1:end,i1);
  if ismember(i1,id)
    plot(x,C);
  end
end

[Brwa]

Thanks Mr Andrei Bobrv. I always appreciate your help

Answer 4

[Brwa]

Thanks you guys, I collected all of your ideas then I come out with new code which can do my job.

Here is the code

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

B=[1; 2; 3];

x =[1 2 3];

for i = 1:3

C = B + A(:,i);
end

Ans =

C1

C2

C3

Now, if i want to plot C2 then i have to make another loop. As I said i can only make sure what do i want to plot after all results of C from the first loop.

for i = 1:3

     C = B + A(:,i);
     C 
  if i==2
    plot(x,C);
  end
end

If you have better idea please share it with us.