MATLAB: Calculate mean monthly from daily values

data miningfor loop

I have a file that is 22281 rows x 5 col. This represents 60 years of daily values. I need to calculate mean monthly values for all years and extract, say, only May, to a new file. The resulting output will be 60 values for mean monthly data for May. This will be to compare col4 to col5 (below).

col1=year
col2=month
col3=day
col4=data1
col5=data2

Please help!

Best Answer

Take a look at the solutions to this question: http://www.mathworks.com/matlabcentral/answers/27088-sort-data-by-day-of-year. You might find some ideas there that help you.

Related Solutions

MATLAB: How to get monthly average from daily data

Not sure what you mean by "without breaking the matrix into some new matrix", but here we go:

x is column with months,

y is data

[G,name] = findgroups(x)
out = splitapply(@mean,y,G)

This will give you max 12 values, one for each month of the year. If you have several years, and you want 12 values per year, then you can do the following trick.

x1 is months (double)

x2 is years (double)

x=cellstr(num2str([x1, x2]))
[G,name] = findgroups(x)
out = splitapply(@mean,y,G)

Better yet, put your data in a timetable and use retime to calculate the monthly average. Here's an example using your data:

data=xlsread('data.xlsx')
t=datetime(data(:,1:3))
T=timetable(t,data(:,4))
T2=retime(T,'monthly','mean')

MATLAB: Calculate mean from daily to monthly values.

dn=datenum('01-01-2008','dd-mm-yyyy'):datenum('31-12-2014','dd-mm-yyyy')
swh=randi(10,numel(dn),1)
[y,m,d] = datevec(dn);
a=[y' m' d']
[ii,jj,kk]=unique(a(:,1:2),'rows')
out=accumarray(kk,(1:numel(kk))',[],@(x) mean(swh(x)))

Best Answer

Related Solutions

MATLAB: How to get monthly average from daily data

MATLAB: Calculate mean from daily to monthly values.

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