How to combine 2 for loops

Hi, I have

 id = [ 1 3; 2 6; 3 2; 4 5; 5 1; 6 4; 7 7];

I will get two new_ids by sorting its column,

 for col=1:c
    new_id{col}=sortrows(id,col);
end

I want to get 2 results from each of the new_id respectively. This means that I will have in total 4 results.

 for m=1:2
    result{m}=id(m:m+1,:);
end

How can i combine all this? Thank you.

[David Sanchez]

It is not very clear what you want to achieve. Could you please give an example or try to explain it in a different way?

[Grace]

For example,

 id = [ 1 3; 2 6; 3 2; 4 5; 5 1; 6 4; 7 7];
for m=1:2
    result{m}=id(m:m+1,:);
end

The code above gives me two sets of array,result{1} and result{2}. But now i sort my initial array which i denoted as "id" by sorting its column, and this will gives me two new_id, I sort it by following:

 id = [ 1 3; 2 6; 3 2; 4 5; 5 1; 6 4; 7 7];
for col=1:c
    new_id{col}=sortrows(id,col);
end

After that i want to run my first "for loop" to this two new_id by using the same code

 for m=1:2
    result{m}=id(m:m+1,:);
end

Means that i need to combine this two loops in order for me to do that. Do i make myself clear?

[Grace]

Here is the code that I created:

id = [ 1 3; 2 6; 3 2; 4 5; 5 1; 6 4; 7 7];
[r c]=size{id);
for col=1:c   
for m=1:2
new_id=sortrows(id,col);
  result{m}=new_id(m:m+1,:);
end
end

My problem here is the output only shows me the loop when col=2, it overwrite the output for col=1, what can I do in order for me to keep both of the results for col=1 and 2?

Answer 1

[David Sanchez]

You were not very clear in your explanation, but I think you want this:

id = [ 1 3; 2 6; 3 2; 4 5; 5 1; 6 4; 7 7];

c=size(id,2);%I'm guessing c = Nº columns in id
result = cell(2); % pre-allocation of 2x2 cell array to hold data
for col=1:c% col=2
    new_id{col}=sortrows(id,col);
    for m=1:2% m=2
        result{m,col}=new_id{col}(m:m+1,:);
    end
end

You will end up with a cell array result whose columns contain the result of your first loop

[Grace]

Hi David,

I can't run the above code, it shows me

 Cell contents assignment to a non-cell
array object.

 Error in 
    new_id{col}=sortrows(id,col);

What is the problem?

[David Sanchez]

I tested it in Matlab 2012a and it works. Try with a temporal variable in between

id = [ 1 3; 2 6; 3 2; 4 5; 5 1; 6 4; 7 7];

c=size(id,2);%I'm guessing c = Nº columns in id
result = cell(2); % pre-allocation of 2x2 cell array to hold data
for col=1:c% col=2
    temp = sortrows(id,col);
    new_id{col} = temp;
    for m=1:2% m=2
        result{m,col}=new_id{col}(m:m+1,:);
    end
end

if it does not work, paste the error and the value of temp