I keep getting the same error when using readtable or readmatrix: Dimensions of arrays being concatenated are not consistent.

A = readtable('data_file.csv')
A = readmatrix('data_file.csv')

When I tell you I have tried everything. Uninstalled and reinstalled Matlab twice. Cleared my cache of all matlab knowledge. I cannot read in data from a csv or text file using readtable and readmatrix for the life of me. Somebody please help. I have tried doing the same exact things on other's computers and it works perfectly. I am convinced my readtable and readmatrix functions are broken.

[Steven Lord]

Does the error occur only for this one particular .csv file (or a corresponding .txt file) or does it happen for all such files?

If you use writematrix to write a matrix to a file, can you then call readmatrix on that file to recreate the matrix? If you run the following lines of code, what happens?

cd(tempdir)
A = magic(5);
writematrix(A, 'samplefile.csv')
B = readmatrix('samplefile.csv');
isequal(A, B) % ought to be true

ans = logical
   1

If this is specific to one particular file, have you checked that all of the rows in the file have the same number of elements?

[Chase]

Hi, thank you so much for your response. I get this error on all such files. I have created many test files and they all give me the same error message. In running your code, I got the following:

Error using readmatrix (line 11)

Dimensions of arrays being concatenated are not consistent.

Error in

untitled2 (line 4)

B = readmatrix('samplefile.csv');

^^^^^^^^^^^^^^^^^^^^^^^^^^^

Answer 1

[Stephen23]

You have likely shadowed the function HEIGHT() or WIDTH() or SIZE() or LENGTH() or NUMEL() or similar:

https://www.mathworks.com/matlabcentral/answers/1575958-readmatrix-not-working-in-2021b

Tell us the exact output from these commands:

which -all height
which -all width

and we might be able to identify a shadowed function.

If no obvious shadowing then tell us what this prints:

try
    B = readmatrix('data_file.csv');
catch ME
    fprintf('Error ID: %s\n', ME.identifier);
    fprintf('Message: %s\n', ME.message);
    fprintf('Error occurred in: %s (line %d)\n', ME.stack(1).name, ME.stack(1).line);
end

or use

dbstop if caught error

to identify the line and function/file and error cause. Let us know where it stops!

For those who are wondering, line 11 of READMATRIX() simply consists of

throw(ME);

and rethrows errors that are caught in the actual functions doing the heavy-lifting.

[Chase]

>> which -all height

C:\Users\chase\OneDrive - Virginia Tech\Documents\MATLAB\height.m

C:\Program Files\MATLAB\R2025b\toolbox\matlab\elmat\height.m % Shadowed

>> which -all width

C:\Program Files\MATLAB\R2025b\toolbox\matlab\elmat\width.m

C:\Program Files\MATLAB\R2025b\toolbox\matlab\bigdata\@tall\width.m % tall method

>>

is this what you are asking for? Thanks again for your patience and assistance.

[Chase]

did it again using dbstop if caught error instead of dbstop if error (which is what i did the first time). Not sure if this makes any difference, thought I'd let you know

[Stephen23]

which -all height
C:\Users\chase\OneDrive - Virginia Tech\Documents\MATLAB\height.m

Problem: you have created a function named HEIGHT which is shadowing the inbuilt HEIGHT function.

Solution: delete or rename your function.

[Chase]

Stephen, I cannot begin to tell you how grateful I am for your assistance. I have been trying to figure this out for over a week now!

Thank you so much. Happy holidays to you and your family.