opening .m file results in "index exceeds the number of array elements"

I've yet to use MATLAB (new user) and since installing I've had issues with trying to open .m files from Finder (Mac). When opening .m file I get a dialog box that says "index exceeds the number of array elements. Index must not exceed 0"

[Benjamin Kraus]

This error indicates that (a) you are running the code instead of editing the code, and (b) there is some kind of mistake in the code in your M-file.

• Are you trying to run (or execute) the code, or are you trying to modify (or edit) the code?
• When you you say "opening", can you describe how you are opening the file? Are you double-clicking on the file in the "Current Folder" browser? Or clicking the "Open" button on the MATLAB tool strip? Or something else?

[Clifton]

I am using Mac's Finder (file explorer) program to open the file (i.e., double-click with the mouse). My goal presently is just to read the script. I can work around the error message by opening with TextEdit. I have a research assistant that is well versed in MATLAB and they were surprised by the error message.

[Walter Roberson]

The most common cause of problems like these, is if you have some third-party function with the same name as a Mathworks-supplied function. For example if you have your own length.m then you can encounter these kind of problems.

Experiment with executing

restoredefaultpath; rehash toolboxcache
savepath

Note this will not work if the extra function is in the default directory.

Answer 1

[Steven Lord]

How are you trying to open the file? Are you calling open or edit with the name of the file as inputs? If so, make sure you don't have a variable with the same name as that function and check that you haven't written your own function by that name that's taking precedence over that function included in MATLAB.

which -all open

/MATLAB/toolbox/matlab/general/open.m
/MATLAB/toolbox/matlab/uicomponents/uicomponents/+matlab/+ui/+container/@ContextMenu/open.m  % matlab.ui.container.ContextMenu method
open is a built-in method                                                                    % Simulink.loadsave.SLXPackageReader method
/MATLAB/toolbox/matlab/graph2d/@scribehandle/open.m                                          % scribehandle method
/MATLAB/toolbox/matlab/serial/@serial/open.m                                                 % serial method
/MATLAB/toolbox/simulink/simulink/upgradeadvisor/@UpgradeAdvisor/open.p                      % UpgradeAdvisor method
/MATLAB/toolbox/instrument/instrument/@icdevice/open.m                                       % icdevice method
/MATLAB/toolbox/shared/instrument/@instrument/open.m                                         % instrument method
/MATLAB/toolbox/sl3d/sl3d/@vrworld/open.m                                                    % vrworld method

which -all edit

/MATLAB/toolbox/matlab/codetools/edit.m
/MATLAB/toolbox/shared/controllib/graphics/+controllib/+widget/+internal/+cstprefs/ToolboxPreferences.m  % controllib.widget.internal.cstprefs.ToolboxPreferences method
/MATLAB/toolbox/shared/controllib/graphics/@resppack/@respplot/edit.m                                    % resppack.timeplot method
/MATLAB/toolbox/matlab/graph2d/@axischild/edit.m                                                         % axischild method
/MATLAB/toolbox/sl3d/sl3d/@vrworld/edit.m                                                                % vrworld method

If you have your own open.m or edit.m that shows up when you execute those commands, rename that file.

[Walter Roberson]

The user indicates they are opening from the finder (Mac) .

I don't recall that the command executed in this situation is documented. I reason that it is more likely open

[Clifton]

I am uncertain if replies to another thread get conveyed to all posters across other threads, so I'll reply to your similar question again here:

I am using Mac's Finder (file explorer) program to open the file (i.e., double-click with the mouse). My goal presently is just to read the script. I can work around the error message by opening with TextEdit. I have a research assistant that is well versed in MATLAB and they were surprised by the error message.

[Steven Lord]

Can you try running those two commands in MATLAB and showing us what they display?