Calculate median values of slices of array associated with histogram bins
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I have an array (array1) which I want to put into histogram bins. I have a second array (array2) which is the same length.
I can sum the values of array2 in each bin with this:
[count, edges, idx] = histcounts(array1,edges);
binsums = accumarray(idx,array2);
But how can I calculate the median values of array2 in each bin?
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Accepted Answer
Star Strider
on 15 Nov 2023
I would use another accumarray call:
binmedians = accumarray(idx+1, (1:numel(idx)).', [], @(x)median(array2(x)))
Creating data and correcting for ‘idx’ having 0 for some elements (making them inappropriate index values) —
array1 = randn(1E+3,1);
array2 = randn(1E+3,1);
edges = 1:9;
[count, edges, idx] = histcounts(array1,edges);
binsums = accumarray(idx+1,array2)
binmedians = accumarray(idx+1, (1:numel(idx)).', [], @(x)median(array2(x)))
.
2 Comments
Star Strider
on 15 Nov 2023
As always, my pleasure!
One such:
binmedians = accumarray(idx+1, (1:numel(idx)).', [], @(x)median(array2(x),'omitmissing'))
There are several others.
.
More Answers (1)
Steven Lord
on 15 Nov 2023
If all you want is the bin numbers, you could also use the discretize function instead of histcounts.
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