Subscripted assignment dimension mismatch.

I am a beginner programmer, but feel like I am missing something pretty fundamental here.

I am trying to make a function that takes 2 variables:

• a string str
• an integer N

It should then make a 1xN matrix containing the input string at each index and output the matrix.

function bigstring = string_multiplication(str,N)
bigstring(1:N) = str;
disp(bigstring);
end

When I call the function in the command window, I get the following message:

>> string_multiplication('Name',5)
Subscripted assignment dimension mismatch.

Error in string_multiplication (line 8)
bigstring(1:N) = str;

I have also tried predefining 'bigstring = zeros(1,N)' and using a for loop and get similar results.

Answer 1

[Fabio Freschi]

You can use repmat and create a char array

function bigstring = string_multiplication(str,N)
  bigstring = repmat(str,N,1);
  disp(bigstring);
end

[Walker Pride]

Thanks, Fabio!

Since I am looking for an 1xN array instead of Nx1, I think I could just flip the N,1 arguments in repmat.

Also, I figured out that single quotations ('Name') create a char datatype. To create a string datatype I needed to use double quotations ("Name").

When 'Name' = str, str is a 1x4 char (instead of a 1x1 string that I would get if I input "Name")

Then when I set bigstring(1:N) = str, each element of bigstring would try to store a 1x4 matrix instead of 1x1.

I ended up fixing it with the following code:

function bigstring = string_multiplication(str,N)
    str = string(str);
    bigstring = string(zeros(1,N));
    for i = 1:N
         bigstring(1,i) = str;
    end
    disp(bigstring);
end

This way whatever is input for str it is automatically converted into a 1x1 string.

This also works:

function bigstring = string_multiplication(str,N)
    str = string(str);
    bigstring(1:N) = str;
    disp(bigstring);     
end