Using "for" to create loops

I am trying to create a loop to have a (ixm)x2 matrix such as:

1 1
1 2
1 3
2 1
2 2
2 3
3 1
3 2
3 3

My formulation is as follows:

i = size(input,1);
m = max(input(:,5));
for indice = 1:i;
    for indice2 = 1:m;
        Zassign = (1,[indice, indice2]);
    end
end

I am missing something in here. If you may help me, I would really appreciate it.

[Taner Cokyasar]

If possible, can I also write a matrix as following:

Z 1 1
Z 1 2
Z 1 3
Z 2 1
Z 2 2
Z 2 3
Z 3 1
Z 3 2
Z 3 3

I am a new MATLAB user. I know MATLAB deals with numbers. However, I just wanted to ask to make sure if that is not possible.

Answer 1

[Stephen23]

Why waste time with a loop? Code vectorization is much more beautiful!

>> [X,Y] = meshgrid(1:3);
>> mat = [X(:),Y(:)]
mat =
   1   1
   1   2
   1   3
   2   1
   2   2
   2   3
   3   1
   3   2
   3   3

And if you really want the Z's you can print them, but they cannot be stored in a numeric matrix (unless you store the character code):

>> fprintf(' Z %d %d\n',mat.')
 Z 1 1
 Z 1 2
 Z 1 3
 Z 2 1
 Z 2 2
 Z 2 3
 Z 3 1
 Z 3 2
 Z 3 3

[Taner Cokyasar]

It definitely works Stephen. Thank you so much for those. I have one more question. What if I want to add a column vector at the end of mat. The column vector I am talking is the result of my question. I just want to show results matched with its corresponding variables.

Let's say:

Z 1 1 0

The zero at the end represents the answer for the variable Z11. I have a column vector of answers for each variable named as "Zvalues".

[Stephen23]

You can use much the same idea. If the results are in a vector Z, then simply concatenate it onto the back:

>> Z = 1:9;
>> [X,Y] = meshgrid(1:3);
>> mat = [X(:),Y(:),Z(:)]
mat =
   1   1   1
   1   2   2
   1   3   3
   2   1   4
   2   2   5
   2   3   6
   3   1   7
   3   2   8
   3   3   9

and for printing you just need to add the appropriate formatting operator to the fprintf string:

>> fprintf(' Z %d %d %d\n',mat.')

[Taner Cokyasar]

You are great Stephen! "%d" was what I was missing. God Bless!

[Stephen23]

@Taner Cokyasar: you should read the fprintf documentation carefully, because there are a lot of options for these formatting operators. Practice and try them to pick one that best suits your needs.

[Taner Cokyasar]

Actually meshgrid is not working for this situation. I just chose a lucky example by using i=3 and m=3. When I tried i=10 and m=3, it doesn't work. Do you have any idea? I mean:

1 1

1 2

1 3

2 1

2 2

2 3

3 1

3 2

3 3

4 1

4 2

4 3

.

.

.

10 1

10 2

10 3

[Stephen23]

Did you read the meshgrid documentation ? You can use two inputs to meshgrid:

>> [X,Y] = meshgrid(1:10,1:3);
>> mat = [X(:),Y(:)]
mat =
     1     1
     1     2
     1     3
     2     1
     2     2
     2     3
     3     1
     3     2
     3     3
     4     1
     4     2
     4     3
     5     1
     5     2
     5     3
     6     1
     6     2
     6     3
     7     1
     7     2
     7     3
     8     1
     8     2
     8     3
     9     1
     9     2
     9     3
    10     1
    10     2
    10     3

[Taner Cokyasar]

After this answer, yes :) I appreciate it.