MATLAB how to display negative values if any in code

This code shows a section of a data sheet. How would I make it so if there is a negative value detected in the table NNeg, it would display the location and then

allow the user to correct it by imputting a replacement value until an positive number is entered.

load Saturated_Table

load SpecificHeat_Data

SAT = SaturatedTable;

SH = SpecificHeatData;

NNeg = SaturatedTable(1:end , 2:end);

if NNeg<0

disp(neg)

end

[Walter Roberson]

Duplicates https://www.mathworks.com/matlabcentral/answers/689089-matlab-finding-negative-numbers-and-showing-where-they-are?s_tid=srchtitle -- you should add onto that one.

Answer 1

[Harry Laing]

One way would be to use a for loop to go through each cell in the matrix and test to see if it is negative, and if so require an input as a replacement. It's not the fastest or most efficient, but it would work:

NNeg = SaturatedTable(1:end , 2:end); 

[NumRows, NumCols] = size(SaturatedTable);

%The code below will move horizontaly across each data point in the matrix, and test < 0

for i = 1:NumRows     % For every Row 
    for j = 1:NumCols % For every Column
        
        if SaturatedTable(i,j)<0 % Perform test
            disp(['Negative Data at point: (',num2str(i),' ',num2str(j),')']) %Display non-negative location
            new_value = input('Please Provide a positive number replacement: ') % Ask for replacement
            
            while new_value(i,j) < 0 % Check input is positive
                new_value = input('Previous input error, please Provide a positive number replacement: ')
            end
            
            SaturatedTable(i,j) = new_value; % Update our table with new value
            
        end
        
    end
end

Note: This wouldnt prevent anyone from entering text instead of a number, so there's probably more checks needed after the input, but as a starter for 10 this should work.