Try this: with(data1, table(ID, Year))
On Tue, Oct 14, 2008 at 10:58 AM, Tom La Bone <[EMAIL PROTECTED]>wrote: > > Assume that I have the dataframe "data1", which is listed at the end of > this > message. I want count the number of lines that each person has for each > year. For example, the person with ID=213 has 15 entries (NinYear) for > 1953. > The following bit of code calculates NinYear: > > for (i in 1:length(data1$ID)) { > data1$NinYear[i] <- length(data1[data1$Year==data1$Year[i] & > data1$ID==data1$ID[i],1]) } > > This seems to work but is horribly slow (some files I am working with have > over 500,000 lines). Can anyone suggest a faster way of doing this, perhaps > a way that does not use a for loop? Thanks. > > Tom > > ID Year NinYear > 209 1971 0 > 209 1971 0 > 213 1951 0 > 213 1951 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1953 0 > 213 1954 0 > 213 1954 0 > 213 1954 0 > 213 1954 0 > 213 1954 0 > 213 1954 0 > 213 1954 0 > 213 1954 0 > 213 1954 0 > 213 1954 0 > 213 1954 0 > 213 1955 0 > 213 1955 0 > 234 1953 0 > 234 1953 0 > 234 1953 0 > 234 1953 0 > 234 1953 0 > 234 1958 0 > 234 1958 0 > 234 1965 0 > 234 1965 0 > 234 1965 0 > 249 1952 0 > 249 1952 0 > > > > -- > View this message in context: > http://www.nabble.com/Doing-a-Task-Without-Using-a-For-Loop-tp19974078p19974078.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. > -- Henrique Dallazuanna Curitiba-Paraná-Brasil 25° 25' 40" S 49° 16' 22" O [[alternative HTML version deleted]]
______________________________________________ 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.