R help - May 2010 - better way to trick data frame structure?

Hi,

I have a data frame where 1 variable is a factor with only 1 level.  I need
the data frame structure to reflect that there are 2 levels for this factor,
even though this is not the case.  I am currently adding extra 'fake'
rows
to the data frame to ensure that 2 levels are present, but this is slowing
processing time in a loop quite a bit. Can I manually specify that this
factor variable has two levels (even though this is lying to R)? 
Thanks,Seth
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Hi

r-help-bounces at r-project.org napsal dne 05.05.2010 07:49:25:
> 
> Hi,
> 
> I have a data frame where 1 variable is a factor with only 1 level.  I 
need
> the data frame structure to reflect that there are 2 levels for this 
factor,
> even though this is not the case.  I am currently adding extra
'fake'
rows
> to the data frame to ensure that 2 levels are present, but this is 
slowing
> processing time in a loop quite a bit. Can I manually specify that this
> factor variable has two levels (even though this is lying to R)? 
Not at all lying. That is why hated factors are useful. Lust add all 
desired levels.
> ff<-factor("M")
> ff
[1] M
Levels: M
> levels(ff)<-c("M","F")
> ff
[1] M
Levels: M F

Regards
Petr
> Thanks,Seth
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> View this message in context: 
http://r.789695.n4.nabble.com/better-way-to-
> trick-data-frame-structure-tp2130470p2130470.html
> Sent from the R help mailing list archive at Nabble.com.
> 
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Thanks, works beautifully and saved hours of run time. -seth
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