MATLAB: Indexing Vector of Variables

indexvector

I have a column vector of numbers (we'll call it A for example). Is there a slick way to go through A and create another column vector (B) of indices? In other words, if a number in A falls in the range of 0-0.1, it will be binned (i.e., indexed) as 1 in B. If a number in A falls in the range of 0.1-0.2, it will be indexed as 2 in B. If a number in A falls in the range of 0.2-0.3, it will be indexed as 3 in B. And so on. Vector B will then serve as my Indexing vector to allocate each number of A to a certain "bin." I'm sure I could write a FOR and/or IF statement to accomplish this. But for the sake of efficiency, I wanted to ask if there was a more efficient and easier way.
Thanks,
M Ridzon

Best Answer

That is what the histogram functions do very easily and efficiently:
https://www.mathworks.com/help/matlab/ref/histc.html
or
https://www.mathworks.com/help/matlab/ref/histcounts.html
or
https://www.mathworks.com/help/matlab/ref/discretize.html
etc.
Here is an example:
>> V = rand(1,10)
V =
    0.8093   0.0174   0.3329   0.4669   0.5331   0.1471   0.9760   0.3909   0.4499   0.3305
>> B = 0:0.1:1; % bin edges
>> [~,idx] = histc(V,B)
idx =
    9    1    4    5    6    2   10    4    5    4
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