Given values and bin edges, find the bin of each value in MATLAB

Question

I have a set of values and I want to find out to which bin each of them belong in more compact, likely vectorized and most importantly faster than the one below,

values = rand(1,3)*50;
bins = 0:10:50;
binValues = nan(size(values));
for valueIndex = 1:length(values)
    dif = bins - values(valueIndex);
    [~,locat] = min(abs(dif));
    %to see on which side it is
    if dif(locat)>0
        locat = locat - 1;
    end
    %if its outside the bins:
    if locat==0 || locat==length(bins)
        locat=nan;
    end
    binValues(valueIndex) = locat;
end

values
bins 
binValues

for example,

values =

   28.6037   37.7998   30.8294


bins =

     0    10    20    30    40    50


binValues =

     3     4     4

Answer 1

Perhaps, take a look at MATLAB's discretize function introduced in R2015a . With this function, you can replace your loop with:

binValues = discretize(values, bin, 'IncludeEdge', 'right');

You can assign values on bin-edges to either the left or right bin with the IncludeEdge parameter. For example, does 10 belong to bin 1 (ie: ..., "IncludeEdge", "left" ) or bin 2 (ie: ..., "IncludeEdge", "right" ).

Finally, note that values outside of the bin range will be assigned bin value of NaN .