Error using save: Argument must contain a character vector

Can somebody give me some insight on how to fix this? I am super new to MatLab.

 load Assignment_4_data
ones_row = ones(1,8);
Q1_1 = [ones_row;Num1;ones_row];
ones_column = ones(10,1);
Q1_2 = [-ones_column, Q1_1, ones_column];
new_row = Q1_2(7,2:9)-2;
Q1_2(7,2:9)= new_row;
data = Q1_2.^2;
save(part_1,'data');

Answer 1

[Cam Salzberger]

Hello Marki,

I assume that you are trying to save your data variable to a MAT file entitled part_1.mat?

In that case, you just need to add single-quotes around part_1 to make it a character vector. Currently, MATLAB is trying to access a variable called part_1, which seems to exist (maybe) but doesn't contain character data.

save('part_1', 'data')

or just use command syntax:

save part_1 data

Also, unless your assignment specifies otherwise, you can just do:

Q1_2(7,2:9) = Q1_2(7,2:9)-2;

No need to make a temporary variable.

-Cam

[Marki Wong]

Oh, wow I was literally just missing those single quotes. Thank you so much for taking the time to help me out!

[Sara Salimi]

What if it is a variable containg a text? I have different directory and seed to save for each them separately in a for loop. I am facing with the same error.

fname=strcat(dirnames(i),'.mat');
save(fname,'X_features','Y_label');

[Cam Salzberger]

Sara, that should work fine. Though if dirnames is a cell array of character vectors, you'll need to use dirnames{i}. If it's a string array, then it's correct as is.

Can you show what happens when you do this:

class(dirnames)
size(dirnames)
disp(dirnames)

Maybe at some point, dirnames(i) does not contain text? You could always run this code to go into debug mode when your error is hit, and see what the issue is:

dbstop if error

-Cam