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Find and replace a specific value in a table

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Hello, I have a table with over 15000 rows and 100 columns. I want to plot the values in columns but I need to turn some of them that are set to -9999 to NaN. And there are -9999 in all my columns( my columns are named)/
I would like to use something like that :
table(table==-9999)=NaN
But I know that I can't use comparator with a whole table so I have to add index :
table(table(:,:)==-9999)=NaN
But it's still not working.
Is there an index that take all columns? Or maybe another solution more simple?
Thank you!

Accepted Answer

Image Analyst
Image Analyst on 21 Apr 2022
Edited: Image Analyst on 21 Apr 2022
You forgot to attach your table so I had to create one.
% Create table data because OP forgot to attach his.
v1 = rand(100, 1);
v2 = rand(100, 1);
v1(1:10) = -9999;
v1(end-4:end) = -9999;
v2(1:15) = -9999;
v2(end-14:end) = -9999;
t = table(v1, v2, 'VariableNames', {'Column1', 'Column2'})
% METHOD 1: uSING table2array()
variableNames = t.Properties.VariableNames;
m = table2array(t);
m(m==-9999) = nan;
tFixed = table(m(:, 1), m(:, 2), 'VariableNames', {'Column1', 'Column2'});
% METHOD 2: USING FOR LOOP
% Now we have our table and we can begin replacing -9999 with NaN.
for col = 1 : width(t)
map9999 = t{:, col} == -9999;
t{map9999, col} = nan;
end

More Answers (2)

Siddharth Bhutiya
Siddharth Bhutiya on 30 Mar 2023
You could use standardizeMissing to do this.
t = table([1;-9999;3],[-9999;NaN;4],[NaN;4;5])
t = 3×3 table
Var1 Var2 Var3 _____ _____ ____ 1 -9999 NaN -9999 NaN 4 3 4 5
t = standardizeMissing(t,-9999)
t = 3×3 table
Var1 Var2 Var3 ____ ____ ____ 1 NaN NaN NaN NaN 4 3 4 5

David Hill
David Hill on 21 Apr 2022
m=table2array(yourTable);%assuming your table is all numbers of the same type
m(m==-9999)=nan;
%then just plot from the matrix

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