How to convert continuous form of data into discrete steps form?

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Chetan Badgujar on 22 Aug 2020
Edited: Cris LaPierre on 26 Aug 2020
I looking for help to convert countinous form of data into discreate steps form.
X = [ 1 3 5 8 10 15 20 25 30 34 38 40 45 50 55 60 65 69 70]
y =[ 1 3 5 4 6 5 8 7 6 7 6 7 6 7 6 7 5 7 0 1]
I want convert X variable in to steps multiple of 5 [0 5 10 15 20 25..] and coresspong values of y betwen these steps should be mean(y). Well I am looking for output in the following format.
x= [5,10,15...]
y=[3,5,5..].
I tried with find(x<5), which gave me indices for calculating the mean (y), but its too laborous method.
Thank you
Adam Danz on 24 Aug 2020
You can flexibly compute the edges using
rg = 0:5:ceil(X/5)*5;

Cris LaPierre on 26 Aug 2020
Try this (uses the data your supplied in the repost). Note that your data in X3 goes to 1.42, not 0.6. It's also unclear if you just want the summarized data, or the full 50,000 rows back. This gives 50,000 rows.
% Define edges of ranges
rg = 0:0.05:0.6;
% Identify groups (
newX3 = discretize(X3,rg,rg(2:end),"IncludedEdge","right");
% Find the max value in each range
Ymean = groupsummary(Y,X3,rg,@mean,"IncludeMissingGroups",false)
newY = discretize(X3,rg,Ymean)
Cris LaPierre on 26 Aug 2020
Edited: Cris LaPierre on 26 Aug 2020
Older versions of MATLAB (before R2018b) require the inputs to groupsummary to be tables. This convert X3 and Y to a table.
data = table(X3,Y);
% Define edges of ranges
rg = 0:0.05:0.6;
% Identify groups (
newX3 = discretize(data.X3,rg,rg(2:end),"IncludedEdge","right");
% Find the max value in each range
Ymean = groupsummary(data,'X3',rg,@mean,'Y',"IncludeMissingGroups",false)
newY = discretize(data.X3,rg,Ymean.fun1_Y)
% Visualize result
plot(X3,Y,'x')
hold on
plot(newX3,newY,'wo')
hold off

R2018a

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