How to do the mean with a condition?

Hello,

Here is my problem, i have a huge matrix. And i have to do the mean for a row but only with a condition, i created a logical vector which contain 1 when i want to include the value and 0 when i don't.

For example

A=
[2 3 4 5 0
 6 7 8 9 1
 7 5 1 2 1
 2 5 6 9 0]

And i want the mean for the second column when the 4th have a value of 1, so mean=6.

Thanks for your help :)

[Image Analyst]

How did you create the logical vector that says whether or not to get the mean of that row?

And I read your last sentence about the second column numerous times and still can't figure out what it means. When the 4th WHAT has a value of 1? When an element in the 4th column has a value of 1 - but it never has a value of 1, only 5,9,2, and 9. What was averaged to get the 6???

[ProjectVOC]

I had a vector with 0,1,2 and 3 which are parameters and i did : complete_data(:,137)=complete_data(:,136)==1;

Sorry it was the 5th column, so it was a(2,2)=7 and a(3,2)=5

[Image Analyst]

I guess I'll leave it to someone who is still not confused by what you're saying to answer.

[ProjectVOC]

Sorry, english isn't my mother tongue.

I find a solution with a loop, not very elegant but fine for the moment.

Thanks for your time.

Answer 1

[Matt J]

 mean(A(logicalVector,:),1)