Splitapply on a matrix of 1X1000

Question

JFz 2018-3-5

评论： JFz 2018-3-5

采纳的回答： Rik

I have a matrix of 1x1000 numbers and my G is 1. When I do the splitapply on it: res = splitapply(@sum, mat, G);

The res Is the sum of the 1000 numbers. What I want is just the one row returned, i.e., res = mat;

How to get that? This is a special case. In general, there are many rows.

Thanks.

Answer 1

Rik 2018-3-5

res = splitapply(@(x) sum(x,1), mat, G);

This is about 10 times slower for mat=rand(1,1000), but it forces the direction of summation. You could also include a conditional statement:

if size(mat,1)==1
    res=mat;
else
    res = splitapply(@sum, mat, G);
end

JFz 2018-3-5

Thanks! I will use the if statement.