Averaging values within bins

Question

MiauMiau 2018-10-28

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/426506-averaging-values-within-bins

评论： Bruno Luong 2022-6-13

y.mat
x.mat

Hi,

I have the two arrays x and y (attached), which I plot with plot(x,y). This is creating "bins" of width 5:

What is the fastest way to average the values within each such bin, such that we end up with one value/bin, especially if we don't want to pre-define bin width?

Thanks

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MiauMiau 2018-10-28

I don't want to have a histogram in the classical sense: I want the mean value within a bin (not the count). Would the histogram function help nevertheless?

Stephen23 2018-10-28

"Would the histogram function help nevertheless?"

Yes, because they can also return the indices.

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Answer 1

Bruno Luong 2018-10-28

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https://ww2.mathworks.cn/matlabcentral/answers/426506-averaging-values-within-bins#answer_343859

load('y.mat')
load('x.mat')
plot(x,y)
edges = (0:5:50);
[~,~,loc]=histcounts(x,edges);
meany = accumarray(loc(:),y(:))./accumarray(loc(:),1);
xmid = 0.5*(edges(1:end-1)+edges(2:end));
figure
plot(x,y)
hold on; 
plot(xmid,meany,'r')

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AnnieLieseMari 2022-6-13

Hi there!

I'm working with a very similar data set and need some help with my code. I know this was posted and answered a while ago, but I would really appreciate the help.

After using the same code you provided, but with my data set and edges of (4.25:0.5:17.75), I am getting an error saying "First input SUBS must contain positive integer subscripts."

I have a data set of x and y values that is upwards of 2000+ data points. It's super big and when I zip it, the Help Center is still saying it's too big. Please let me know if you'd like me to provide a sample of maybe 20 or so data points to help out.

I think the main reason this is happening is that my data has NaN values in it. Though, I'm not sure how to remove those. Of course, if I remove the x values, I have to preserve the y values so the other pairs still match up.

Bruno Luong 2022-6-13

Simply remove the bad data:

keep = isfinite(x) & isfinit(y);
x = x(keep);
y = y(keep);
... do the rest

Make sure the extrem edges cover entirely your data.

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Answer 2

Steven Lord 2018-10-28

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/426506-averaging-values-within-bins#answer_343872

Do you want to use histogram or histcounts to bin the data, or are you looking for something more of a moving average, where the value of the averaged signal at a particular time is the mean of the data for that time and some data points before and after that time? If the latter, see movmean.