Finding the n'th element satisfying a condition
29 Ansichten (letzte 30 Tage)
Ältere Kommentare anzeigen
I have a huge array A (about 30 million elements) and I'm trying to extract the n'th element satisfying a condition A == b. Currently, I' using the following:
x = max(find(A == b,n))
Is there a more efficient way to do this since I need to do this several times in my code?
Thanks.
0 Kommentare
Akzeptierte Antwort
Sean de Wolski
am 7 Mai 2012
That looks good to me. The only thing that might make it faster would be to index instead of use max():
idx = find(A==B,n,'first')
idx(end)
Weitere Antworten (2)
Thomas
am 7 Mai 2012
Seems to be the fastest way of doing this.. Index might make it faster (though I doubt it..) try timing it..
0 Kommentare
Walter Roberson
am 7 Mai 2012
I am not sure why you are using max() ?
t = find(A == b, n, 'first');
t(end)
If you are doing this repeatedly, what is varying, and what is known at the time you want to start the first search? If you know all the values you will be searching on, then the three-output version of ismember() might be appropriate.
Siehe auch
Kategorien
Mehr zu Matrices and Arrays finden Sie in Help Center und File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!