I have a set of data where I have recorded values in sets of 3 readings (so as to be able to obtain a general idea of the SEM). I have them recorded in a list that looks as follows, which I am trying to collapse into averages of each set of 3 points:
I want to collapse essentially each 3 rows into one row where the average data value is given for that set. In essence, it would look as follows:
This is something I know how to do basically in Excel (i.e. using a Pivot table) but I am not sure how to do the same in MATLAB. I have tried using accumarray but struggle with knowing how to incorporate multiple conditions essentially. I would need to create a subs array where its number corresponds to each unique set of 3 data points. By brute force, I could create an array such as:
subs = [1 1 1; 2 2 2; 3 3 3; 4 4 4; ...]'
using some looping and have that as my subs array, but since it isn't tied to the data itself, and there may be strange hiccups throughout (i.e. more than 3 data points per set, or missing data, etc.). I know there must be some way to have this sort of Pivot-table-esque grouping for something like this, but need some help to get it off the ground. Thanks.
Here is the input data in text form:
Subject Flow On/Off Values
1 10 1 2.20
1 10 1 2.50
1 10 1 2.60
1 20 1 5.50
1 20 1 6.10
1 20 1 5.90
1 30 1 10.10
1 30 1 10.50
1 30 1 10.50
1 10 0 1.90
1 10 0 2.20
1 10 0 2.30
1 20 0 5.20
1 20 0 5.80
1 20 0 5.60
1 30 0 9.80
1 30 0 10.20
1 30 0 10.20
2 10 1 5.70
2 10 1 6.00
2 10 1 6.10
2 20 1 9.00
2 20 1 9.60
2 20 1 9.40
2 30 1 13.60
2 30 1 14.00
2 30 1 14.00
2 10 0 5.40
2 10 0 5.70
2 10 0 5.80
2 20 0 8.70
2 20 0 9.30
2 20 0 9.10
2 30 0 13.30
2 30 0 13.70
2 30 0 13.70