Your 'x' has length 2, so x[[3]] cannot be calculated ('subscript out of bounds' is what I get). You can check for this with length(x)<3.
In general, you want to be more precise: 'does not have a value', 'is NULL', and 'is empty' are not synonymous. I'm not sure what 'does not have a value' means to you. NULL is a value with a certain type, 'NULL', and length, 0. seq_len(0) is empty, but not NULL, since it has type 'integer'. c(1,NA) contains a 'missing value'. Can you explain what what you are trying to check for, giving some context? Bill Dunlap TIBCO Software wdunlap tibco.com On Sat, Dec 20, 2014 at 7:58 AM, Ragia Ibrahim <ragi...@hotmail.com> wrote: > > Hello, > Kindly I have a list of lists as follow > x > [[1]] > [1] 7 > > [[2]] > [1] 3 4 5 > > as showen x[[3]] does not have a value and it has NULL, how can I check on > this > how to test if x[[3]] is empty. > > thanks in advance > Ragia > > [[alternative HTML version deleted]] > > ______________________________________________ > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see > 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 -- To UNSUBSCRIBE and more, see 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.