How can I replace NaN in a table with a zero?

I have a table in MatLab titled data, and there are NaN values in the first couple rows of the table. I would like to change these values to zero, but any way I've tried gives an error message because it is a table and not a matrix or array. If anyone has a way to change these values it would be greatly appreciated! Thanks!

Answer 1

[R]

Hi @Elyse,

If you're working with a table in MATLAB and you want to replace NaN values with zeros, you'll need to handle the data column-wise or cell-wise depending on the data type of each column in the table.

You need to iterate over each column, check data type if replacing NaN makes sense or is necessary and then use logical indexing or isnan function for it.

Here's a sample code that demonstrates the same:

% Sample table
Age = [NaN; 22; NaN; 45];
Salary = [NaN; 55000; 60000; NaN];
Name = ["John Doe"; "Jane Doe"; "Alice"; "Bob"];
T = table(Age, Salary, Name);

disp('Original Table:');

Original Table:

disp(T);

    Age    Salary       Name   
    ___    ______    __________

    NaN      NaN     "John Doe"
     22    55000     "Jane Doe"
    NaN    60000     "Alice"   
     45      NaN     "Bob"     

% Loop through each variable in the table
for varName = T.Properties.VariableNames
    % Get the column data
    columnData = T.(varName{1});
    
    % Check if the column is numeric
    if isnumeric(columnData)
        % Replace NaN with 0
        columnData(isnan(columnData)) = 0;
        % Assign the modified column back to the table
        T.(varName{1}) = columnData;
    end
    % For non-numeric data, you can define other replacements if necessary
end

disp('Modified Table:');

Modified Table:

disp(T);

    Age    Salary       Name   
    ___    ______    __________

     0         0     "John Doe"
    22     55000     "Jane Doe"
     0     60000     "Alice"   
    45         0     "Bob"     

Hope it helps!

[Elyse]

Thanks, using just the one line:

columnData(isnan(columnData)) = 0;

worked for me without the loop

Answer 2

[Torsten]

https://uk.mathworks.com/matlabcentral/answers/231096-replace-nan-s-in-table-with-zero