How to vectorize this code with logical idexing

Hi all,
I have the following code, how can I avoid the for to make it faster?
a=[10:5:50];
b=[10:20:50];
c=rand(size(a));
for i=length(b)-1
d=c(a>=b(i) & a<b(i+1));
end
thanks
cheers

1 个评论

Since you're only storing the last values of d in each iteration, you can skip the for-loop completely:
i = length(b)-1
d = c(a>=b(i)) & a<b(i+1))
but I am pretty sure you intend to do something else.
What should happen with the values of d obtained in the iterations 1 to length(b)-2?

请先登录,再进行评论。

 采纳的回答

a=[10:5:50];
b=[10:20:50];
c=rand(size(a));
[~,ii] = histc(a,b);
d = accumarray(ii(:),c(:),size(b(:)),@(x){x})

3 个评论

Hi Andrei,
thanks. I tried with my code but the empty bins at the end of the array are skipped. Here an axample:
a=[10:5:20, 55:5:90];
b=[10:20:170];
c=rand(size(a));
[er,ii] = histc(a,b);
d = accumarray(ii(:),c(:),[],@(x){x});
d should be a 8 elements array instead it is 4 elements array. How could I do to take into account the empty bins at the end of the array?

请先登录,再进行评论。

更多回答(0 个)

类别

帮助中心File Exchange 中查找有关 Matrix Indexing 的更多信息

产品

标签

Community Treasure Hunt

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

Start Hunting!

Translated by