finding index of several values within a vector efficiently
조회 수: 2 (최근 30일)
이전 댓글 표시
I am trying to find the index of 'several' values within an array/vector. For instance, I have a vector [1 2 5] and matrix X=[1 5 4 3 2]. I want it to return [1 5 2]. I could write a for loop that finds each values in that vector such as find(X==1), then find(X==2) ..., but I was hoping there is a vectorized way to do this. Thanks.
댓글 수: 0
채택된 답변
the cyclist
2012년 12월 2일
v = [1 2 5];
X = [1 5 4 3 2];
[tf loc] = ismember(v,X);
"loc" is the vector you want.
댓글 수: 0
추가 답변 (1개)
Matt Fig
2012년 12월 2일
편집: Matt Fig
2012년 12월 2일
idx = [1 2 5];
X = [1 5 4 3 2];
vals = X(idx) % linear indexing.
댓글 수: 2
the cyclist
2012년 12월 2일
If I am interpreting Jimmian's question correctly, this method only gives the correct answer to the example because of a numerical coincidence. For example, if
X = [0 0 0 0 0 1 5 4 3 2]
then I think he wants the output to be
loc = [6 10 7]
and not
[0 0 0].
참고 항목
카테고리
Help Center 및 File Exchange에서 Matrix Indexing에 대해 자세히 알아보기
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!