On Wed, Aug 27, 2008 at 12:11 PM, Josip Dasovic <[EMAIL PROTECTED]> wrote: > Hello: > > As someone making the move from STATA to R, I'm finding it difficult at times > to perform basic tasks in R, so forgive me if I've missed an obvious and > easily obtained solution to my problem. I've searched the help guides and > the archives and have not been able to find a solution that works. > > I have a data frame with thousands of observations that looks something like > this: > > YEAR MONTH DAY COUNTRY REGION PROVINCE > CITY > 1994 1 22 Sri Lanka South Asia Northern (Province) > Pungudutivu > 1994 1 25 Sri Lanka South Asia Central (Province) > Kandy > 1994 2 26 Sri Lanka South Asia Central (Province) > Kandy > 1994 2 28 Sri Lanka South Asia Eastern (Province) > Wakianeri > 1994 6 28 Sri Lanka South Asia Eastern (Province) > Valachenai > 1994 6 31 Sri Lanka South Asia Central (Province) > Kandy > 1995 3 1 Sri Lanka South Asia North (Province) > Kilinochchi > 1995 3 6 Sri Lanka South Asia Western (Province) > Colombo > 1995 7 15 Sri Lanka South Asia Northern (Province) > Mankulam > 1995 7 23 Sri Lanka South Asia Northern (Province) Point > Pedro > 1995 9 25 Sri Lanka South Asia Northern (Province) > Kilali > ... > > What I would like to do is to calculate the total number of observations by > unique combinations of the values of (some of the) variables above. > > For example, I would like to know how many observations (i.e. rows) have the > values YEAR==1994 and MONTH==1. > > In the end, I'd like a table that looks like this: > > YEAR MONTH #OBS > 1994 1 2 > 1994 2 2 > 1994 3 0 > 1994 4 0 > 1994 5 0 > 1994 6 2 > 1994 7 0 > 1994 8 0 > 1994 9 0 > 1994 10 0 > 1994 11 0 > 1994 12 0 > 1995 1 0 > 1995 2 0 > 1995 3 2 > 1995 4 0 > ... > > I do need to fill out the table with all the possible combinations, even > where there are no observations with that combination in the data set. > At first, it seemed like this would not be think that aggregate is probably > the way to go, but there doesn't seem to be an appropriate summary function > (FUN) available. Thanks in advance for any help in this matter,
For this, and other related problems, you might want to look at the reshape package - http://had.co.nz/reshape Hadley -- http://had.co.nz/ ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
