Hi, If you don't return(x) or x at the end, set.seed(5) list1<-lapply(1:3,function(i) data.frame(col1=sample(c(1:5,""),10,replace=TRUE), value=rnorm(10),stringsAsFactors=FALSE)) lapply(list1,function(x) x[x==""]) #[[1]] #[1] "" ""
#[[2]] #character(0) #[[3]] #[1] "" "" "" "" "" "" lapply(list1,function(x) x[x==""]<-NA) #[[1]] #[1] NA # #[[2]] #[1] NA # #[[3]] #[1] NA lapply(list1,function(x) x[x==""]<-rep(NA,length(x[x==""]))) #[[1]] #[1] NA NA # #[[2]] #logical(0) # #[[3]] #[1] NA NA NA NA NA NA lapply(list1,function(x) {x[x==""]<-NA;return(x)}) #or lapply(list1,function(x) {x[x==""]<-NA;x}) #or lapply(list1,function(x) {x[x==""]<-rep(NA,length(x[x==""]));x}) [[1]] # col1 value #1 2 -0.6029080 #2 5 -0.4721664 #3 <NA> -0.6353713 #4 2 -0.2857736 #5 1 0.1381082 #6 5 1.2276303 #7 4 -0.8017795 #8 5 -1.0803926 #9 <NA> -0.1575344 #10 1 -1.0717600 ---------------------- A.K. ________________________________ From: Dominic Roye <dominic.r...@gmail.com> To: arun <smartpink...@yahoo.com> Sent: Tuesday, January 8, 2013 1:06 PM Subject: Re: [R] Logical operator and lists hi, Can you explain me why without ;x at the end, i get only NA? > c [[1]] [1] NA [[2]] [1] NA 2013/1/8 arun <smartpink...@yahoo.com> HI, >This should also work: > > > set.seed(5) > list1<-lapply(1:3,function(i) >data.frame(col1=sample(c(1:5,""),10,replace=TRUE), >value=rnorm(10),stringsAsFactors=FALSE)) > > lapply(list1,function(x) {x[x==""]<-NA;x}) > >A.K. > >----- Original Message ----- >From: Dominic Roye <dominic.r...@gmail.com> >To: R help <r-help@r-project.org> >Cc: >Sent: Tuesday, January 8, 2013 7:16 AM >Subject: [R] Logical operator and lists > > >Hello R-Helpers, > >I have a slight problem with the expresion data[data==""] <- NA which works >well for a data.frame. But now i must use the same for a list of >data.frames. > >My idea is data[[]][data==""] but it don´t work. > >Thanks!! > >Dominic > > > [[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. > > ______________________________________________ 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.