indexing error: ()-indexing must appear last in an index expression

Do you know what is wrong with my indexing below? Thanks.

vars = {'Cs' 'beta' 'As' 'TCI' 'TWI' 'hs'}
tmp = cell(size(dem))  % create 20x1 supercell
out = tmp;
tmp2 = size(vars) % create 6x1 subarrays
out2 = zeros(tmp2);
for i=1:numel(dem)
    for j=1:numel(vars)
        *out{i} = out2(:,:,j)(Cs{i}, beta{i}, As{i}, TCI{i}, TWI{i}, hs{i});*
    end
end

Error: ()-indexing must appear last in an index expression.

Answer 1

[the cyclist]

In MATLAB you cannot index into an array that you've already indexed into, so you cannot do this

out{i} = out2(:,:,j)(Cs{i}, beta{i}, As{i}, TCI{i}, TWI{i}, hs{i})

But assuming the rest of your code is OK (which I could not check), then you could define a temp variable

 out2_tmp = out2(:,:,j);
 out{i} = out2_tmp(Cs{i}, beta{i}, As{i}, TCI{i}, TWI{i}, hs{i})

[Sam]

Thanks, Cyclist. That made progress yet led to a dreaded error I've hit numerous times but don't fully understand. This is my first attempt at a nested for loop. Can you offer more help? There is no other add'l code, although FYI each 'vars' is a 20x1 cell of n x m arrays.

vars = {'Cs' 'beta' 'As' 'TCI' 'TWI' 'hs'}
tmp = cell(size(dem))
out = tmp;
tmp2 = size(vars)
out2 = zeros(tmp2);
for i=1:numel(dem)
  for j=1:numel(vars)
      out2_tmp = out2(:,:,j);
      out{i} = out2_tmp(Cs{i}, beta{i}, As{i}, TCI{i}, TWI{i}, hs{i});
  end
end

Subscript indices must either be real positive integers or logicals.

[the cyclist]

I can't really help debug your code, because it is not self-contained. However, I can give insight into that error.

x = [2 7 6 3];

idx_valid_integers = [1 3 4 2];
idx_valid_logical  = [true true false true];
idx_invalid        = [-1 0];

% Valid indexing
y = x(idx_valid_integers);

% Also valid indexing [using logical indexing]
y = x(idx_valid_logical);

% Not valid indexing (index is neither positive integer nor logical)
y = x(idx_invalid); % This will give you that same error.

The first two ways of indexing work, because I am either telling MATLAB a particular element (by its position) or by applying a logical "mask" to the entire vector.

But the third way does not work. What is the "-1" or "zeroth" element of a vector. It makes no sense.

Somehow, that is what you are doing in your code.

Answer 2

[Bhargavkrishna Kondreddy]

% Importing all the 300 files

files = dir( 'imageset1_*.txt'); for i=1:numel(files) A{i} = dlmread( files(i).piv, '\t', 3 , 0 ); end

% Summation of X-components of the 300 files

Xsum ='A('1)(:,3); for k = 2:299 Xsum=Xsum+A(k)(:,3); end () indexing must appear last in an index expression at

[Walter Roberson]

MATLAB does not have implicit multiplication. You need to add * as appropriate.