Find and replace a specific value in a table

206 vues (au cours des 30 derniers jours)
Pablo SERIS
Pablo SERIS le 21 Avr 2022
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!

Réponse acceptée

Image Analyst
Image Analyst le 21 Avr 2022
Modifié(e) : Image Analyst le 21 Avr 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

Plus de réponses (2)

Siddharth Bhutiya
Siddharth Bhutiya le 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 le 21 Avr 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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