Combining duplicate entries in a data array

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Addo
Addo 2018-3-14
评论： Batuhan Arik 2021-10-7
Hello,
I have two vectors x and y with corresponding data points. x is in sorted order, but may have double entries, e.g.
x = [0.1, 5, 5, 5, 14.5, 16, 16, 21];
y = [70, 8, 2, 3.5, 6, 5, 2.5, 3.3];
What I would like to do is find the double entries of x and combine the corresponding y values (by summing them up), so that
x_new = [0.1, 5, 14.5, 16, 21];
y_new = [70, 8+2+3.5, 6, 5+2.5, 3.3] = [70, 13.5, 7.5, 3.3];
However I struggle to manage this sufficiently. I have tried to use the function
[x_new, ia, ic] = unique(x);
but I don't know how to efficiently use these values further. Any ideas? :)
Thanks for your help!

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Stephen23
Stephen23 2018-3-14
编辑：Stephen23 2018-3-14
Use accumarray:
>> x = [0.1, 5, 5, 5, 14.5, 16, 16, 21];
>> y = [70, 8, 2, 3.5, 6, 5, 2.5, 3.3];
>> [xnew,~,idx] = unique(x);
>> ynew = accumarray(idx(:),y(:))
ynew =
70.0000
13.5000
6.0000
7.5000
3.3000
  2 个评论
Batuhan Arik
Batuhan Arik 2021-10-7
Hello, did the exact same thing, it seems to be working. I get x_new and y_new as they are supposed to come out. However, when I try
bar(x_new,y_new);
the plot comes out empty.

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