[R] Lattice bwplot(): Conditioning on one factor

[David Winsemius]

On Sep 28, 2012, at 7:49 AM, Rich Shepard wrote:

>  I'm not able to create the proper syntax to specify a lattice bwplot() for
> only one of two conditioning factors.

Wouldn't that involve specifying the 'subset' parameter (if bwplot accepts a subset argument) or using the 'subset' function to pass the desired rows to the data argument if it doesn't?

> 
>  The syntax that produces a box plot of each of the two conditioning
> factors is:
> 
> bwplot(quant ~ param | era, data=mg.d, main='Dissolved Magnesium', ylab='Concentration (mg/L)')
> 
>  What I've tried unsuccessfully are:
> 
> bwplot(quant ~ param | factor(era=='Pre-mining'), data=mg.d,
> main='Magnesium', ylab='Concentration (mg/L))
> 
> bwplot(quant ~ param | era, data=mg.d, main='Magnesium', ylab='Concentration
> (mg/L)', subset=era('Pre-mining'))
> 
> plus slight variations of the above. None work.
> 
>  Please point me to what I've missed in specifying only one of two
> conditioning factors for the plot.
> 
> 
-- 

David Winsemius, MD
Alameda, CA, USA