If isnan then set to text

for i=1:length(Table1.Columnname)
    if isnan(Table1.Columnname(i))
        Table1.Columnname(i) = 'NO';
    end
end

I have the above code but it does not work. I think it has to do with how I have defined Table1.Columnname(i) = 'NO';

Please can someone tell me how to code this properly for my isnan i.e. to set that cell in the table to "NO"?

[dpb]

Format your code so it's legible, please...

But, the problem is more than likely that since you have a table, there's no NaN but a string 'NaN' is my guess. Have you tested w/ debugger or w/ debugging output what

   isnan(Table1.Columnname(i))

returns for the cell in question?

Answer 1

[Walter Roberson]

What datatype is Table1.Columnname ? If it is a char array (string) then you cannot store two elements 'N' and 'O' in one location. If it is a cell array then you need to work with its contents rather than with the cell, such as Table1.Columnname{i} = 'NO' . And as Duane points out, you need to know whether the cell would hold NaN (a numeric value) or 'NaN' (a string)

[Matthew]

Thank you Walter / Duane for your reply.

Okay - I have imported this table into Matlab and the field is a cellVector. But then I converted the text string to numbers. This code works perfectly fine when replacing 'NO' with e.g. 7. Any suggestions please?

[Walter Roberson]

When you convert the text string to numbers, what value do you want the 'NO' to become?

[Matthew]

The source data is a mixture of numbers and NaN. After the text string to numbers conversion, the source data is still numbers and NaN. Now I want to convert where there is a NaN to set to a text 'NO'. This is the difficulty I am experiencing.

[Walter Roberson]

YourCellArray(cellfun(@isnan, YourCellArray)) = {'NO'};

[Matthew]

Thanks Walter!

[Image Analyst]

I'm confused. Do you really have a table? How did you import? Did you do

T = readtable(yourFileName);

? Let's use the example in the help, and replace one of the items in the cell with nan and see what happens:

T = table(['M';'F';'M'],[45;32;34],...
    {'NY';nan;'MA'},logical([1;0;0]),...
    'VariableNames',{'Gender' 'Age' 'State' 'Vote'})

class('T.State') % Reports char.
whos T.State % Strangely silent - reports nothing.
YourCellArray = T.State % Extract column 3 into a cell array.
% The following line bombs.
YourCellArray(cellfun(@isnan, YourCellArray)) = {'NO'};

Can anyone explain why (1) whos is silent, and (2) why Walter's code bombs?