Correlation coefficent for vectors (of unequal lengths).

조회 수: 20 (최근 30일)
Anna
Anna 2013년 7월 25일
Hi,
I have two separate vectors (A and B) which I want to caculate '[r,p] = corrcoef(A,B)' for. They are the same length but both contain 'NaN' so I can't use corrcoef. Both vectors follow a time series so I can't remove the nans separately in each vector as the rows of data will then be out of sequence.
Is there a way of removing an entire row in both A and B if one of them contains a nan on a particular row so that they remain in synch with each other?
If not is there another method I can use?
Thanks

채택된 답변

Daniel Shub
Daniel Shub 2013년 7월 25일
편집: Daniel Shub 2013년 7월 25일
First make some dummy data
A = 1:10;
A(2) = nan;
B = 1:10;
B(4)=nan;
Then combine the arrays into a matrix so it is easy to work with
C = [A; B];
Then only keep columns for which not any of the rows are nan
D = C(:, ~any(isnan(C)))
Finally split the matrix into two new arrays
Aprime = D(1, :);
Bprime = D(2, :);

추가 답변 (1개)

Narges M
Narges M 2013년 7월 25일
use isnan() function to skip those rows
  댓글 수: 5
Narges M
Narges M 2013년 7월 25일
the ~isnan(A) function will give you 1s for numbers and 0s for nan elements. by adding the two together (assuming your A and B matrix are exactly the same length), you will get 2s on those rows containing numbers in both A and B. using find() function you would have that index in the number form.
so for example:
A = [ 1 4 7 NaN 8 NaN 3];
B = [NaN 6 4 5 1 NaN 9];
then
idx = find(~isnan(A)+ ~isnan(B)==2)
will give you:
idx = [2 3 5 7];
which is correct. now you can use
corrcoef(A(idx),B(idx)).
Anna
Anna 2013년 7월 25일
Oh I see that clearly now! Thanks!

댓글을 달려면 로그인하십시오.

카테고리

Help CenterFile Exchange에서 Creating and Concatenating Matrices에 대해 자세히 알아보기

Community Treasure Hunt

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

Start Hunting!

Translated by