Hi
> PLEASE do read the posting guide! ****************************** On 25 Aug 2005 at 20:28, A Mani wrote: > Hello, > Is it safe to use tapply when the result will be of dim 20000 > x 10000 or more ? In my PC R crashes. or gave you an error message? I tried this > df<-data.frame(A=as.factor(sample(1:10000,100000, replace=T)),B=as.factor(sample(100000:110000,100000, replace=T)), num=rnorm(100000)) > ttt<-tapply(df$num, list(df$A,df$B), diff) and got Error: cannot allocate vector of size 390664 Kb In addition: Warning messages: 1: Reached total allocation of 1000Mb: see help(memory.size) 2: Reached total allocation of 1000Mb: see help(memory.size) > and the result with smaller data sets are df1<-data.frame(A=as.factor(sample(1:2,100000, replace=T)),B=as.factor(sample(10:11,100000, replace=T)), num=rnorm(100000)) ttt1<-tapply(df1$num, list(df1$A,df1$B), diff) > ttt1 10 11 1 Numeric,24933 Numeric,25141 2 Numeric,24992 Numeric,24930 df<-data.frame(A=as.factor(sample(1:1000,100000, replace=T)),B=as.factor(sample(10000:11000,100000, replace=T)), num=rnorm(100000)) ttt<-tapply(df$num, list(df$A,df$B), diff) > > ttt[1:2,1:5] 10000 10001 10002 10003 10004 1 NULL NULL NULL Numeric,0 NULL 2 NULL NULL NULL Numeric,0 NULL > so you are probably receiving humonguous table of NULLs, zeros and few nonzero entries. You probably need to use different approach Cheers Petr The code used was on a 3-col > data frame with two factor cols and a numeric column. The fn was diff > . data form being <A, B, Num> tapply(data$A, list(data$A, data$B), > diff) > > -- > A. Mani > Member, Cal. Math. Soc > > ______________________________________________ > R-help@stat.math.ethz.ch mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide! > http://www.R-project.org/posting-guide.html Petr Pikal [EMAIL PROTECTED] ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html