Mean of array columns with condition

4 次查看（过去 30 天）
Mariella Dreißig
Mariella Dreißig 2019-11-18
回答： Philippe Lebel 2019-11-18
I have an array of which I need the mean of each column (X). Additionally, I have a logical array of which rows meet a condition and should be included in the mean (Y).
Naturally, the mean function in MATLAB calculates each column mean, but when I insert the logical vector for the row selection, the mean is calculated for the whole array. How do I fix this for computing the mean of each column in X for the valid indices of Y?
When entering
means_active = mean(X(Y), :);
I get the error 'Reference to a cleared variable mean.', though I don't want to use any variable 'mean' but the built-in function 'mean'.
  3 个评论
显示 1更早的评论
Mariella Dreißig
Mariella Dreißig 2019-11-18
编辑：Mariella Dreißig 2019-11-18
I already copied the line of code I'm talking about, I don't know how to illustrate more.
means_active = mean(X(Y(:,1) < cutoff), :);
Mariella Dreißig
Mariella Dreißig 2019-11-18
I found a workaround though, thanks :)

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Philippe Lebel
Philippe Lebel 2019-11-18
I tested my solution with these matrices:
a = rand(6,3)
B=[1;0;1;1;0;1];
means_active = mean(a(logical(B)),2);
seems to work for me. (i was forced to cast B as logical because i manually declared the values inside the list as integers)

类别

在 Help Center 和 File Exchange 中查找有关 Creating and Concatenating Matrices 的更多信息

标签

产品

Community Treasure Hunt

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

Start Hunting!

Translated by