[R] Odp: tabulating 2 factors weighting by a third var

[Petr PIKAL]

Hi


r-help-bounces at r-project.org napsal dne 20.12.2010 07:07:35:

> Hi,
> 
> This must be an easy one but so far I haven't find a way out...
> 
> I have a data frame such as:
> 
> $ v1    : Factor w/ 5 levels
> $ v2    : Factor w/ 2 levels
> $ v3    : Class 'difftime'  atomic [1:6666]
> 
> basically v1 and v2 are factors, while v3 is a variable containing the 
> duration of certain activities (values ranging from 11 to 45000 sec, no 
missing values)
> 
> How can I get a table such that v1 levels will show as rows, v2 levels 
as 
> columns and v3 is the weight by which table(v1,v2) is weighted? That is, 

> instead of getting the count of occurences in each of the 10 cells of 
table
> (v1,v2) I would like to get the sum(v3), how can it be done?

xtabs(v3~v1+v2, data=your.data.frame)

is other option.

Regards
Petr


> 
> Thanks,
> Luca
> 
> Luca Meyer
> www.lucameyer.com
> IBM SPSS Statistics release 19.0.0
> R version 2.12.1 (2010-12-16)
> Mac OS X 10.6.5 (10H574) - kernel Darwin 10.5.0
> 
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