Why changes my string into a double in a for loop

Hello!

When I want to change a cell in a matrix with the original value NULL into 'C', the 'C' turns into the value 67. This is my code:

for j=1:99
    percentage2 = j/99
    mDataTest(m,1) = str2double(data{1}{j});
    mDataTest(m,2) = 0;

      for i = 3:50
          percentage1 = j/50       
          if(strcmp(data{i}{j},''))
              mDataTest(m,i) = 'C'; 

          elseif(strcmp(data{i}{j},'NULL'))
              mDataTest(m,i) = 'C' ;         
          else
             mDataTest(m,i) = str2double(data{i}{j}); %make matrix with data               
          end
      end
          m=m+1;
          n=3;
  end

Where data is a matrix filled with strings and numeric values. The goal of this is to change all values that are '' or 'NULL' into a string. Eventually I want to replace all 'C' with the median of that vector. Can someone help me?

Answer 1

[Matt J]

If you don't want mDataTest to be double, then don't use str2double when you create it.

[Rosalie van der Weide]

I only want to change the NULL and the '' into 'C' but the rest can change into a double. Is my function correct?

[Walter Roberson]

It is not possible to assign both numeric and characters to the same array except by using cell array.

[Matt J]

This might be what you want. As Walter says, mDataTest must be kept as type cell array.

 for j=1:99

    percentage2 = j/99

    mDataTest{m,2} = 0;

      for i = 3:50
          percentage1 = j/50   

          if(strcmp(data{i}{j},'') || strcmp(data{i}{j},'NULL'))
              mDataTest{m,i} = 'C';         
          else
             mDataTest{m,i} = str2double(data{i}{j}); 
          end
      end
          m=m+1;
          n=3;
  end

[Rosalie van der Weide]

It works! Thank you very much!!