[R] omit empty cells in crosstab?

Dieter Menne dieter.menne at menne-biomed.de
Fri Apr 24 21:47:08 CEST 2009


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




More information about the R-help mailing list