index out of bounds because numel(x)=1.

I am trying to create a loop to call different variables at each time but I am getting this message "index out of bounds because numel(x)=1."

What am I doing wrong?

> x(1)=50;
>> x(2)=45;
>> x(3)=89;
>> x(4)=88;
>> for i=1:1:4
x=x(i);
end
??? Attempted to access x(2); index out of bounds
because numel(x)=1.

[Lokesh Ravindranathan]

The problem here is that once you get into your for loop, you create a new variable x which is of size 1*1. In the second iteration of your loop, you are trying to access the second element of this array, which is not available. Try using a different variable to the lhs of the assignment operation.

[Mevlüt Yalaz]

you have to initialize first the dimension of x. Then you get what you want

[Walter Roberson]

No, that is incorrect, Mevlüt Yalaz . The problem is that one value is extracted from x and that one value is used to overwrite all of x.

Answer 1

[per isakson]

This script

     x(1)=50; 
     x(2)=45; 
     x(3)=89; 
     x(4)=88; 
     disp(x)
     for ii=1:1:4 
         x=x(ii); 
         disp(x)
     end

returns

        50    45    89    88
        50
    Attempted to access x(2); index out of bounds because numel(x)=1. 
    >>

The vector x is overwritten by the first value of x

Answer 2

[Kalyne]

Thanks for the answer! I am asking this because I am trying to solve the problem below. But now when I try to run, it appears :

"??? Cell contents reference from a non-cell array object.

Error in ==> TESTAR at 35
    problem_statement=problem_statement{i}"

the program:

clear;
run('..\psg_load_libraries');
addpath('..');

clear problem_statement;

problem_statement{1}= textread('problem_DEA_Hospital.txt','%s', 'whitespace', '');
problem_statement{2}= textread('problem_DEA_Hospital2.txt','%s', 'whitespace', '');

% read and print problem statement

for i=1:1:2  

      problem_statement=problem_statement{i};
  problem_statement=problem_statement{i};
  fprintf('Problem statement:\n%s', problem_statement);

end

[per isakson]

Your text would be easier to read if you format/markup it; use the {}Code button

    clear; run('..\psg_load_libraries'); addpath('..');
    clear problem_statement;

    problem_statement{1}= textread('problem_DEA_Hospital.txt' ...
                                   ,'%s', 'whitespace', '');
    problem_statement{2}= textread('problem_DEA_Hospital2.txt' ...
                                   ,'%s', 'whitespace', '');

    for ii=1:1:2
        problem_statement=problem_statement{ii};
        problem_statement=problem_statement{ii};
        fprintf('Problem statement:\n%s', problem_statement);
    end

Based on this code, it is not possible (for me) to understand what you want to do. The code says that you want to read two files and write something. Maybe the files each contains a single line.

[Walter Roberson]

Your line

          problem_statement=problem_statement{ii};

takes the ii'th element of problem_statement, and writes that over top of all of problem_statement, so afterwards problem_statement is probably going to be a string instead of a cell array of strings.