Error: How to store values from a for loop?

I am using getDataTips on the File Exchange to extract data tip info.

I wrote a for loop so that I can extract just the index value since the getDataTips extracts [X,Y], index, and [R,G,B] where the index values are 466.833, 405.573, and so on. (See attached image).

There are 11 data tips I would like to extract.

And I'm trying to store all the values from the for loop into an array using the following:

s = 11;
a1 = zeros(11,1);

for i = 1:s
    x(i+1) = content{1,1}{i,1}{2};
    a1(11,i) = x(i+1); 
end

This outputs an error message which says: "Unable to perform assignment because the left and right sides have a different number of elements" for the line: x(i+1) = content{1,1}{i,1}{2}.

When I do,

for i = 1:s
    content{1,1}{i,1}{2}
end

It outputs:

ans = 'Index 466.833'

ans = 'Index 405.573'

I know that I didn't write my for loop coding correctly when attempting to put it into an array, but I'm not sure what's wrong because this is my first time writing a for loop.

So any help on this would be much appreciated!

[Image Analyst]

It really depends on what's in content. Wee need to know that to know how to reference the element inside it. But to clarify what you're doing, I'd break it apart into separate terms like this:

% Extract the contents of the (1,1) cell.  
% It is also a cell array, but with s rows and unknown number of columns.
cell1 = content{1,1}; 
% Preallocate cell arrays x and a.
x = cell(s + 1, 1);
a = cell(11, s + 1);
% Loop over the first s rows of cell1.
for k = 1 : s
    % Get contents of the k'th cell in column 1.
    % For some reason, it also appears to be a cell array of at least 2 elements.
    thisCell = cell1{k, 1}
    % Get the second cell of thisCell and assign it to x.
    % x will also be a cell array.
    x(k + 1) = thiscell(2);
    a1(11, k) = x(k + 1); 
end

It's a really complicated structure having cell arrays inside cell arrays inside cell arrays. You should really simplify it somehow.

PLEASE ATTACH content IN A .MAT FILE if you need anymore help.

save('Gabrielle.mat', 'content');

Also see the FAQ on cell arrays:

https://matlab.fandom.com/wiki/FAQ#What_is_a_cell_array.3F

[parslee]

Attached is the .mat file!

Answer 1

[Walter Roberson]

s = 11;
a1 = zeros(s,1);

for i = 1:s
    x = sscanf(content{1,1}{i,1}{2}, 'Index %f');
    if isempty(x)
        x = nan;
    else
         x = x(1);
    end
    a1(i) = x;
end

[parslee]

Thank you so much!!