Hi Jonathan, Try this:
# list of data frames mylist <- list(d1 = matrix(rnorm(100), ncol = 10), d2 = matrix(rnorm(100), ncol = 5), d3 = matrix(rnorm(100), ncol = 20)) # max number of rows max(do.call(c, lapply(mylist, nrow))) # [1] 20 HTH, Jorge On Thu, Aug 19, 2010 at 11:42 AM, Jonathan <> wrote: > Hi All, > Anyone know how to quickly query some summary information on the > components of a list? > > For example, I have a list that contains dataframes (originally > generated by using split() on one large data frame). > > > I simply want to know the number of rows in the longest dataframe from the > list. > > Example, if my list has 3 data frames, and the first has 2 rows, the > second 8 rows, and the third 3 rows, I want to ask something like: > > > max(nrow(myList)) > which would ideally return "8". > > > but this is obviously wrong syntax. > > Currently, I'm looping through each of the data frames in the list, > searching for the max rows, but I'm sure there must be a faster way. > > Thanks, > Jonatahn > > ______________________________________________ > 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. > [[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.