Finding the n'th element satisfying a condition
29 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
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 Commenti
Risposta accettata
Sean de Wolski
il 7 Mag 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)
Più risposte (2)
Thomas
il 7 Mag 2012
Seems to be the fastest way of doing this.. Index might make it faster (though I doubt it..) try timing it..
0 Commenti
Walter Roberson
il 7 Mag 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.
Vedere anche
Categorie
Scopri di più su Matrices and Arrays in Help Center e File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!