Converting Excel columns to a vector

I am trying to access a specific column from different files and convert them into a matrix to be used later but I am running into problems and I'm not sure what I am doing wrong. Here is the part of my code I am trying to do it in, if anyone can tell me what I'm doing wrong I would greatly appreciate it.

 for i = 1:3                % Loop over the files

    a = xlsread(dataFiles{i});  % Load the data

    c = a(:,3);  % takes the third column from the file

    hf(:,i) = c*(100^2); % converts the values and makes a matrix
 end

Is it that I need to convert the cells to a matrix using cell2mat?

[Conrad]

Could you provide the error message (if any)?

[Daniel Jednorozec]

Sure, sorry about that.

??? Subscripted assignment dimension mismatch.

Error in ==> trajtest at 16
    hf(:,i) = c*(100^2);

[Nirmal]

it means that the size of hf and size of c are not same. See the size of both hf and c using size() function.

Answer 1

[Nirmal]

   hf=[];
   for i = 1:3                % Loop over the files

      a = xlsread(dataFiles{i});  % Load the data

      c = a(:,3);  % takes the third column from the file

      hf =[hf c*(100^2)]; % converts the values and makes a matrix
   end

This should work for you.

[Daniel Jednorozec]

Thank you for the help. It's now giving me this error message

??? Error using ==> horzcat
CAT arguments dimensions are not consistent.

Error in ==> trajtest at 18
    hf =[hf c*(100^2)];

[Nirmal]

do you know before hand how many rows are there? the error is because you have empty hf. if you dont know then not so elegant way would be to have a loop inside your main loop. Error is saying it needs to know the row size of the matrix.

[Daniel Jednorozec]

Generally speaking there seems to tend to be 328 rows, but I recently had a file that went for double the time (the rows represent half second data marks), so it can go longer sometimes.

Answer 2

[nanren888]

Are the columns always the same length?

If the dimensions, length of hf(:,i) & c are different you may need to consider

hf(ran,k) = c....

Like Conrad said, can you post the error message?

[Daniel Jednorozec]

Columns are always the same length in this case.

Answer 3

[Daniel Jednorozec]

Ok, I figured out the problem. Apparently the first file is being treated as if it is somehow a different length than the other two files, so when I went from file 2 to file 3 it worked perfectly and printed to the excel file exactly as I wanted. So now I just need to see what exactly is different about the first file and I should have what I was looking for. Thank you everyone for your help.

Answer 4

[Sidra Khalid]

how i write this program

Answer 5

[Sidra Khalid]

this is the remaining part..anyone help me please..is convert it from excel to matlab or matlab to exicel?