MATLAB: Index exceeds matrix dimensions using sprintf by calling mat files

for loop sprintfindex exceeds matrix dimensionsmat filessprintf

Can someone help me with the following error?
Index exceeds matrix dimensions.
Error in Lateral_Position (line 28)
  eval(sprintf('x=[TP%d_BaseLine(:,2)]',i));
_________________________________________________________________
%%Load Data
filenames = {'TP2_BL.mat','TP3_BL.mat','TP4_BL.mat','TP5_BL.mat','TP6_BL.mat','TP7_BL.mat','TP8_BL.mat','TP9_BL.mat','TP10_BL.mat','TP11_BL.mat','TP12_BL.mat','TP13_BL.mat','TP14_BL.mat','TP15_BL.mat','TP16_BL.mat','TP17_BL.mat','TP18_BL.mat','TP19_BL.mat'}; 
for kk = 1:numel(filenames)
    load(filenames{kk})
end
disp('Cell data BL loaded')
disp('-------------------------------------------------------------------')
Ldist=[];
for i=2:19
    eval(sprintf('x=[TP%d_BaseLine(:,2)]',i));
    Ldist=[Ldist;x];
end
Rdist=[];
for i=2:19
    eval(sprintf('x=[TP%d_BaseLine(:,4)]',i));
    Rdist=[Rdist;x];
end

Best Answer

Two important changes to make:
  1. Do NOT use eval.
  2. load into an output variable.
If you had named the variables inside each .mat file with exactly the same names then your processing would be much simpler too: in contrast to what some beginners think, it is much simpler to process a sequence of .mat files if they contain exactly the same variable names.
How to improve your code depends on how many variables there are in each .mat file, and what their names are: you have not told us this, which makes it harder to help you. Assuming that each .mat file contains one variable then you can easily do something like this (untested as I don't have any sample files):
F = {'TP2_BL.mat','TP3_BL.mat','TP4_BL.mat','TP5_BL.mat','TP6_BL.mat','TP7_BL.mat','TP8_BL.mat','TP9_BL.mat','TP10_BL.mat','TP11_BL.mat','TP12_BL.mat','TP13_BL.mat','TP14_BL.mat','TP15_BL.mat','TP16_BL.mat','TP17_BL.mat','TP18_BL.mat','TP19_BL.mat'};
%S = dir('TP*_BL.mat'); % why not just use DIR ?
%F = natsortfiles({S.name}); % download from File Exchange.
C = cell(size(F));
for kk = 1:numel(F)
    S = load(F{kk});
    C(kk) = struct2cell(S);
end
M = vertcat(C{:});
Ldist = M(:,2);
Rdist = M(:,4);
If there are multiple variables in each .mat file, then you can select which one to import by using the regular expression syntax.
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