Thanks. On 30 April 2010 12:14, Erik Iverson <er...@ccbr.umn.edu> wrote: > Wincent wrote: >> >> Dear all, I have a list like this: l <- list(list(a=1,b=NULL), >> list(a=2,b=2)) >> I want to find out the elements with value of NULL and replace them with >> NA. >> The actual case has a very long list, so manually find out and replace >> them is not an option. >> I can use for loop to do this, but I want to know if there is >> vectorized way (or other ways) to do it? >> > Note: > > You have provided a list *of lists*. Is that what you actually have? If > so, > > Solution 1: > > Change whatever is generating the NULL values to NA in the first place
Yes, it is a list of lists. I realized the returned value might have NULL after I have the data. I just need to deal with it. You are right, when I knew that, I will generate NA in the first place. > Solution 2: > > lapply(l, function(x) lapply(x, function(x) ifelse(is.null(x), NA, x))) Cool. that is what I want. Thanks gain. > -- Wincent Rong-gui HUANG Doctoral Candidate Dept of Public and Social Administration City University of Hong Kong http://asrr.r-forge.r-project.org/rghuang.html ______________________________________________ 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.
