small example: a<-c(1.1, 2.1, 9.1) b<-cut(a,0:10) c<-data.frame(b,b) d<-table(c) dim(d) ##result: c(10, 10)
But only 9 of the 100 cells are non-zero. If there were 10 columns, the table have 10 dimensions each of length 10, so have 10^10 elements, too much even to fit in memory Dieter Menne wrote: > > sjaffe <sjaffe <at> riskspan.com> writes: > >> >> I have data with many factors, each taking many values. However, only >> relatively few combinations appear in the data, ie have nonzero counts, >> in >> other words the resulting table is sparse. Say we have 10 factors each >> with >> 10 levels. The result of table() would exceed the memory space (on a >> 32bit >> machine). Is there any way to produce a table with empty cells omitted? >> (without first producing the whole table and then removing rows.) > > It would be easier if you had a reproducible base example, but I > suggest to create ONE new factor of the pasted levels using unique(), > and creating a table of these. > > Dieter > > ______________________________________________ > 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. > > -- View this message in context: http://www.nabble.com/omit-empty-cells-in-crosstab--tp23222263p23224071.html Sent from the R help mailing list archive at Nabble.com. ______________________________________________ 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.
