How to group data points

Hello,

I have a set of data that I would like to perform analysis on, and it's something like:

[150 151.1 149.6 150.2 146.1 145.6 144.1 144.9 145.2 139.9 140.6 138.9 135.4 135.1 134.9 135.9 135.2 129.9 129.89 130.6]

I would like to group the data to 150, 145, 140, etc... I have tried to manipulate it using rounding/ceiling, etc.. but I couldnt figure out how to group it correctly because it varies too much, and another problem is that the number of data points arent always the same. Once I can group it, I would like to find the average of the data for each set. Is there a way to do this?

Thanks for the help!

[Azzi Abdelmalek]

Can you post the expected result for this case?

[Max Bernstein]

sure, it would be something like the following, with the second column being the average.

[150 150.2250
 145 145.1800
 140 139.8000
 135 135.3000
 130 130.3900]

Answer 1

[Matt J]

X=floor(X/5)*5

[Max Bernstein]

Thank you Matt, this was an elegant/simple solution that I would've never thought off!

Answer 2

[Matt J]

Or this,

   edges=120:5:170;
   [~,~,bin] = histcounts(X,edges);

   X=edges(bin)

Answer 3

[Azzi Abdelmalek]

A=[150 151.1 149.6 150.2, 146.1 145.6 144.1 144.9 145.2, 139.9 140.6 138.9]
[a,b]=histc(A,[135:5:150 155])
out=accumarray(b',(1:numel(b))',[],@(x) {A(x)})
celldisp(out)

To get the mean of each group

outmean=accumarray(b',(1:numel(b))',[],@(x) {mean(A(x))})

Answer 4

[Prabakar kg]

arr = [150 151.1 149.6 150.2 146.1 145.6 144.1 144.9 145.2 139.9 140.6 138.9 135.4 135.1 134.9 135.9 135.2 129.9 129.89 130.6];

HISTCOUNTS is used to group the data

[cnt, edges, bin] = histcounts(arr, 125:5:155);

ACCUMARRAY to calculate SUM on the grouped data

 sum = accumarray(bin', arr');

Calculate the AVERAGE. Note that this could be done in the previous step. I separated these to improve readability

 avg = sum./cnt';

Hope this helps.

[Prabakar kg]

Below was the result

 avg =

129.8950
132.7500
136.7333
143.2000
146.6250
150.4333