Converting Excel columns to a vector

Question

Daniel Jednorozec 2012-7-13

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/43592-converting-excel-columns-to-a-vector

回答： Sidra Khalid 2018-12-22

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?

3 个评论
显示 1更早的评论隐藏 1更早的评论

Daniel Jednorozec 2012-7-13

在 MATLAB Online 中打开

Sure, sorry about that.

??? Subscripted assignment dimension mismatch.
Error in ==> trajtest at 16
    hf(:,i) = c*(100^2);

Nirmal 2012-7-13

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.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Nirmal 2012-7-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/43592-converting-excel-columns-to-a-vector#answer_53499

在 MATLAB Online 中打开

   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.

3 个评论
显示 1更早的评论隐藏 1更早的评论

Nirmal 2012-7-14

编辑：Nirmal 2012-7-14

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 2012-7-16

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.

请先登录，再进行评论。

Answer 2

nanren888 2012-7-13

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/43592-converting-excel-columns-to-a-vector#answer_53496

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?

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Daniel Jednorozec 2012-7-13

编辑：Daniel Jednorozec 2012-7-14

Columns are always the same length in this case.

请先登录，再进行评论。

Answer 3

Daniel Jednorozec 2012-7-17

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/43592-converting-excel-columns-to-a-vector#answer_53809

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.