Adding row to matrix in a loop
显示 更早的评论
I have a folder with many files (file_1, file_2 ... file_n), each of them contains variables (A, B, C ...). I need to work with several files (number of files varies) that I specifically choose from the folder (eg. file_1, file_7, file_22, ... file_m) - load the file, calculate some stuff and save the result as a new row to a matrix and then do this for another file etc.
I ´ve been thinking of using for loop to load and calculate, but I can´t figure out how to add a new row to a matrix after every loop. I tried "cat", but it didn´t work the way I need. Or is there a better solution?
And furthemore I need to plot the results in one graph the way I can specify the plot details for a group of files (eg. plot the first 10 results in red, the next ones in green, etc.). I can´t do it manually, because there are dozens of files.
Thanks in advance!
采纳的回答
If and only if the matrices have the same number of columns, you can concatenate two matrices vertically using,
M = [m1; m2]; % where m1 and m2 are matrices with the same number of columns.
To add a new row,
M(end+1,:) = NaN; % or 0, or any other scalar value.
Another solution would be to save the matrices within a cell array and concatenate them later, after the loop; again, equal column numbers are required.
C = cell(n,1);
for i = 1:n
C{i} = mat; % mat is a matrix
end
M = vertcat(C{:});
Once the matrix is complete, the plot() function will plot one line object per column
plot(M, '-')
3 个评论
Peter Till
2020-4-18
编辑：Peter Till
2020-4-18
Adam Danz
2020-4-18
Thanks for pointing out that typo, Peter. I fixed it in the answer so it doesn't cause future confusion.
Your updated version looks good except for two small stylistic corrections you can make:
- Indent the lines within the for-loop (ctrl + a to select all; ctrl + i for smart indentation),
- Suppress the output from the first line of the for-loop by adding a semicolon to the end of the line (I realize it's probably just a demo-line).
Peter Till
2020-4-18
更多回答（0 个）
类别
在 帮助中心 和 File Exchange 中查找有关 Loops and Conditional Statements 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
