MATLAB Answers

Fastest way to replace NaNs by empty cells in a table

27 views (last 30 days)
Blue
Blue on 25 Jun 2020
Commented: Adam Danz on 30 Jun 2020
Hi,
I need to replace the NaNs in the columns a and b by empty cells. The code below works but it is pretty slow. Is there a faster way to do this ?
a = rand(1, 1000000)'; a(1:10000) = NaN;
b = rand(1, 1000000)'; b(1:10000) = NaN;
c = repelem({'A101'}, 1000000)';
t = table(a, b, c);
var_names = t.Properties.VariableNames;
for ii = 1:length(var_names)
if ~iscell(t.(var_names{ii}))
t.(var_names{ii}) = cellstr(num2str(t.(var_names{ii})));
idx = contains(t.(var_names{ii}), 'NaN');
t.(var_names{ii})(idx) = {''};
end
end
Thank you,

  1 Comment

Adam Danz
Adam Danz on 30 Jun 2020
I urge you not to do this. The table variables in columns 1 and 2 are numeric and NaN values indicate missing values. To replace the NaN values with emtpy cells, all of your numeric values will have to converted to cells. That not only looks ugly but it makes the table more difficult to work with.
If you're writing the table to a file and do not want NaN values printed, there are other ways around that.
Converting the numeric values to cells just so the NaN values can appear as empty will likely cause more problems than it aesthetically solves.

Sign in to comment.

Accepted Answer

Fangjun Jiang
Fangjun Jiang on 25 Jun 2020
M=10;N=5;
a = rand(1, M)'; a(1:N) = NaN;
b = rand(1, M)'; b(1:N) = NaN;
c = repelem({'A101'}, M)';
t = table(a, b, c);
t.a=num2cell(t.a);
t.a(cellfun(@isnan,t.a))={''}

  0 Comments

Sign in to comment.

More Answers (0)

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!