Indexing of unknown dimensional matrix

by

For the general case where J can be any length (which I assume always matches the number of dimensions in M), there are a couple options you have:

  1. You can place each entry of J in a cell of a cell array using the num2cell function, then create a comma-separated list from this cell array using the colon operator:

    cellJ = num2cell(J);
output = M(cellJ{:});

  2. You can sidestep the sub2ind function and compute the linear index yourself with a little bit of math:

    sizeM = size(M);
index = cumprod([1 sizeM(1:end-1)]) * (J(:) - [0; ones(numel(J)-1, 1)]);
output = M(index);

More Related Contents:

  1. On shape-agnostic slicing of ndarrays
  2. How to select a submatrix (not in any particular pattern) in Matlab
  3. resizing 3D matrix (image) in MATLAB
  4. How can I find the maximum value and its index in array in MATLAB?
  5. f(x) = 1 for -0.5
  6. find unknown value in matrix using MATLAB [closed]
  7. Finding islands of zeros in a sequence
  8. How can I plot a function with two variables in Octave or Matlab?
  9. How should I update the data of a plot in Matlab?
  10. Automatically plot different colored lines
  11. How do I set default values for functions parameters in MATLAB?
  12. Matlab ode solvers: changing state and specified time
  13. How to divide an image into blocks in MATLAB?
  14. Access m-files in a subfolder without permanently adding it to the path
  15. Example of 10-fold SVM classification in MATLAB
  16. Vectorizing the Notion of Colon (:) – values between two vectors in MATLAB
  17. Reading CSV files with MATLAB?
  18. What’s the difference between & and && in MATLAB?
  19. How can I count the number of elements of a given value in a matrix?
  20. Determining the number of occurrences of each unique element in a vector
  21. Unicode characters in MATLAB source files
  22. How to draw horizontal and vertical lines in MATLAB?
  23. How do I divide matrix elements by column sums in MATLAB?
  24. Is it possible in matlab to explicitly format the output numbers?
  25. Content-Based Image Retrieval and Precision-Recall graphs using Color Histograms in MATLAB
  26. MATLAB debugging: smarter way to stop the code with an specific condition?
  27. Generating all combinations with repetition using MATLAB
  28. Implementing anonymous functions in Fortran
  29. Customize dbstop in MATLAB
  30. How to apply a low-pass or high-pass filter to an array in Matlab?

Leave a Comment