Histogram with different sized bins and edges to illustrate wave periods

I have a set of data (waveperiods) with corresponding number of observations as seen below.

waveperiods = [9 10 11 12 13 14 15 16 17 18 19 20 21]

observations = [1 5 14 22 28 5 6 2 1 0 1 0 0]

i.e a period of 9 is observed 1 time, and a period of 10 is observed 5 times etc....

I would like to make a histogram of the data, BUT with like a class system.

class 1 should contain all periods between 0 and 9.5

class 2 should contain all periods between 9.5 and 10.5 etc...

class 9 should contain all periods between 16.5 and 30.

Then the histogram should be nice and normal-ish like in the picture below.

However, I dont understand how to control the edges and make the desired groups...

I am stuck with the following code:

waveperiods = [9:21];
observations = [1 5 14 22 28 5 6 2 1 0 1 0 0];

groups = [0 9.5:1:16.5 30]; %Ive tried to make the intervals/groups....

Please help, thanks!

Answer 1

[Ajay Pattassery]

The following code will plot the above bar graph

waveperiods = (9:21);
observations = [1 5 14 22 28 5 6 2 1 0 1 0 0];
groups = [0 9.5:1:16.5 30];
 
obsInRange = zeros(1,length(groups)-1);
rangeLength = length(groups)-1;
for i=1:rangeLength
   waveperiodsIndex =  waveperiods >= groups(i) & waveperiods < groups(i+1);
   obsInRange(i) = sum(observations(waveperiodsIndex));        
end
 
bar(1:rangeLength,obsInRange);

[Henning Eimstad]

Awesome! Thanks!