Multiple Variable For Loop

Hi

I have so far written this for loop

for i = 1:VgStep
  for start = 1:VgStep:endPoint-VgStep+1
      for step = VgStep:VgStep:endPoint
Vd{j}{i} = x(start:step);
Id{j}{i} = y(start:step);
      end
  end
end

I appologise for not explaining what all the terms are, but what I need is combine all those for's into one, because I end up just getting the same value for all my Vd{j}{i} terms

I'll explain better if it is needed

[Adam Parry]

you can just imagine VgStep and end point are just two numbers like 3 and 9 if that helps and j comes from another outside loop

[John Petersen]

Can you give an example of what you want? All we have to go on is your code, which doesn't do what you want so we have to just guess. also, start and step are reserved words.

[Adam Parry]

ah ok.

so here is some data

x   y   Vg
0   1    0
-1  2 0
-2  3    0
0   4    -1
-1  5    -1
-2  6  -1
0   7   -2
-1  8  -2
-2  9   -2

I need to split the data into three separate arrays

so I want

 Vd{1}{1} = [0,-1,-2] Id{1}{1} = [1,2,3]
 Vd{1}{2} = [0,-1,-2] Id{1}{2} = [4,5,6]

etc.

but i realised that the inside loops all finish before i can loop over to start a new cell.

How can I prevent this?

[Walter Roberson]

John, neither start nor step are reserved words. See http://www.mathworks.com/help/techdoc/ref/iskeyword.html

Answer 1

[Albert Yam]

In the code posted, you do not have 'j' (this might be elsewhere in your code), in your example, not even sure why you need it.

Since you know what your step size is, you don't need to loop it, the way it is now, seems incorrect. This is what I see from your start:stop. When start > stop , you will get an empty index.

1:3, 1:6, 1:9, 4:3, 4:6, 4:9, 7:3 (error), 7:6 (error), 7:9

Do you understand how the following works?

i = 1;
for start = 1:VgStep:length(Vg)  %what does this count?
  Vd{i} = x(start:start+2);  %try to understand the indexing here
  Id{i} = y(start:start+2);
  i=i+1;                     %how is this affected by 'start'?
end

[Adam Parry]

Thank you

This is exactly what i was looking for