I have "NewCell" that's a cell with 1 row and 6 columns; in which column, there is another cell with 1 column and "k" rows. If the row "k" in NewCell (1,1) is 0, I want to know the average from values in another file (Preos2013S1)

sum=0;
i=0;
for k=0:size(Preos2013S1)

      if NewCell{1,1} == 0
     sum=sum+Preos2013S1(k,6);
     i=i+1;
      end
  end

mediacons_0=sum/i;
histogram(mediacons_0)

It does not work because Undefined operator '==' for input arguments of type 'cell'. What do I need to change?

Answer 1

[Walter Roberson]

It is firmly recommended that you do not use sum as the name of a variable, as that interferes with using the important sum function. That tends to lead to bugs, and confuses other people reading the code.

You should never use size() with a single parameter as one of the input parameters to the colon operator (":") because the colon operator is only defined when the parameters are scalars but size() with only a single parameter always returns a function. You should either use length() or use size() with two inputs to indicate which dimension you are taking the size of.

You are iterating over a size, but you are starting from 0 instead of 1. That is likely to lead you to either indexing at 0 or indexing out of bounds.

Your test should be

        if NewCell{1,1}{k} == 0

[Eduardo Rocha]

 cons0=0;
 i=0;

 for k=0:length(Preos2013S1)
    if NewCell{1,1}{k} == 0
    cons0=cons0+Preos2013S1(k,6);
    i=i+1;
    end
end

However, "Cell contents indices must be greater than 0". NewCell (1,1) has only '0' or [] in each row. What should I do?

[Walter Roberson]

As I wrote above,

"You are iterating over a size, but you are starting from 0 instead of 1. That is likely to lead you to either indexing at 0 or indexing out of bounds."

0 is not a valid index in MATLAB; why are you trying to use it to index Preos2013S1 ?

[Eduardo Rocha]

Sorry for not noticing that part of your answer. Thank you very much, once more!