Average IF NaN counting
1 vue (au cours des 30 derniers jours)
Afficher commentaires plus anciens
Hi,
I have a 20*207 matrix which contains numbers and NaN.
I need to average each column if the amount of NaN is <5. If the number of NaN is >=5 then I would like to remove that column from the matrix. How can I do it? I've been trying some stuff but I'm not able to achieve it.
thanks.
1 commentaire
Geoff Hayes
le 6 Nov 2017
Afonso - what have you been trying? Please copy and paste your code to this question so that we can get an idea of what you have attempted and determine why it is not working. Presumably you are using isnan to determine which elements in your column are NaN...
Réponse acceptée
Robert
le 6 Nov 2017
Some test data
x = randn(20, 207);
x(randi(numel(x), 800, 1)) = nan;
Identify the NaNs with isnan and count the number per column with sum. Then select the columns that have fewer than 5 NaNs.
good_enough = sum(isnan(x)) < 5;
x = x(:, good_enough);
And use nanmean to take the average of the remaining columns.
avg = nanmean(x);
If you don't have the stats toolbox, try the following
the_nans = isnan(x);
num_nans = sum(isnan(x));
good_enough = num_nans < 5;
x = x(:, good_enough);
the_nans = the_nans(:, good_enough);
num_nans = num_nans(:, good_enough);
x(the_nans) = 0;
avg = sum(x);
avg = avg ./ (20 - num_nans);
Plus de réponses (0)
Voir également
Catégories
En savoir plus sur Numeric Types dans Help Center et File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!