[R] Faceted bar plot shows wrong counts (ggplot2)

[Hadley Wickham]

And it's now fixed in the dev version.
Hadley

On Tue, Mar 13, 2012 at 11:37 AM, Helios de Rosario
<helios.derosario at ibv.upv.es> wrote:
> Michael,
>
> Thanks for the pointer to the discussion in the ggplot list. It seems
> that the reason of this behaviour of facet_grid() is already known and
> being discussed by the developers of ggplot2.
>
> facet_grid() reduces the original data frame with unique() before
> applying the stats.  If the data frame has any other column that
> prevents duplicated rows, counts are correctly computed.
>
> E.g.
>
> diamonds25 <- droplevels(diamonds[1:25,]) # Keep all columns
>
> # Everything else as before:
> base  <-  ggplot(diamonds25,  aes(fill  =  cut))  +
>  geom_bar(position  =  "dodge")  +
>  opts(legend.position  =  "none")
>  base  +  aes(x  =  cut)  +
>  facet_grid(.  ~  color)
>
>
> Helios
>
>>>> El día 12/03/2012 a las 20:59, "R. Michael Weylandt"
> <michael.weylandt at gmail.com> escribió:
>> You get the "good" behavior with
>>
>> base + aes(x = cut) + facet_wrap(~ color, ncol = 5)
>>
>> so this seems buggy to me.
>>
>> If someone here doesn't step forward with more insight, I'd forward
> it
>> to the ggplot list to see if one of the developers there can give an
>> explanation or possibly make the official call that it's a bug.
>>
>> There was another report of a possible bug in facet_grid() today
> that
>> could be related:
>>
> https://groups.google.com/group/ggplot2/browse_thread/thread/5213ac35da6b36d
>
>> 4
>>
>> Michael
>>
>> On Mon, Mar 12, 2012 at 7:16 AM, Helios de Rosario
>> <helios.derosario at ibv.upv.es> wrote:
>>> I have encountered a problem with faceted bar plots. I have tried
> to
>>> create something like the example explained in the ggplot2 book (see
> pp.
>>> 126-128):
>>>
>>> library(ggplot2)
>>> mpg4  <-  subset(mpg,  manufacturer  %in%
>>> c("audi",  "volkswagen",  "jeep"))
>>> mpg4$manufacturer  <-  as.character(mpg4$manufacturer)
>>> mpg4$model  <-  as.character(mpg4$model)
>>>
>>> base  <-  ggplot(mpg4,  aes(fill  =  model))  +
>>> geom_bar(position  =  "dodge")  +
>>> opts(legend.position  =  "none")
>>> base  +  aes(x  =  model)  +
>>> facet_grid(.  ~  manufacturer)
>>>
>>> That example works fine; the bar heights are just the same as the
>>> counts in the table:
>>>
>>> table(mpg4[,1:2])
>>>          model
>>> manufacturer a4 a4 quattro a6 quattro grand cherokee 4wd gti jetta
> new
>>> beetle
>>>  audi        7          8          3                  0   0     0
>>>    0
>>>  jeep        0          0          0                  8   0     0
>>>    0
>>>  volkswagen  0          0          0                  0   5     9
>>>    6
>>>          model
>>> manufacturer passat
>>>  audi            0
>>>  jeep            0
>>>
>>> But in other cases this does not occur. For instance, take a small
>>> subset of data(diamonds):
>>>
>>> diamonds25 <- droplevels(diamonds[1:25,2:3])
>>> table(diamonds25)
>>>           color
>>> cut         E F H I J
>>>  Fair      1 0 0 0 0
>>>  Good      1 0 0 1 4
>>>  Very Good 1 0 3 1 4
>>>  Premium   3 1 0 1 0
>>>  Ideal     1 0 0 1 2
>>>
>>> And change the variables mapped in the previous plot:
>>>
>>> base  <-  ggplot(diamonds25,  aes(fill  =  cut))  +
>>> geom_bar(position  =  "dodge")  +
>>> opts(legend.position  =  "none")
>>> base  +  aes(x  =  cut)  +
>>> facet_grid(.  ~  color)
>>>
>>> I see all bars with height = 1.
>>> I have ovserved this problem (wrong bar heights, but not always =
> 1),
>>> in other cases when all counts are very small or zero.
>>> What's wrong here?
>>>
>>> Regards,
>>> Helios
>>>
>>> sessionInfo()
>>> R version 2.14.2 (2012-02-29)
>>> Platform: i386-pc-mingw32/i386 (32-bit)
>>>
>>> locale:
>>> [1] LC_COLLATE=Spanish_Spain.1252  LC_CTYPE=Spanish_Spain.1252
>>> [3] LC_MONETARY=Spanish_Spain.1252 LC_NUMERIC=C
>>> [5] LC_TIME=Spanish_Spain.1252
>>>
>>> attached base packages:
>>> [1] stats     graphics  grDevices utils     datasets  methods
> base
>>>
>>> other attached packages:
>>> [1] ggplot2_0.9.0
>>>
>>> loaded via a namespace (and not attached):
>>>  [1] colorspace_1.1-1   dichromat_1.2-4    digest_0.5.1
>>> grid_2.14.2
>>>  [5] MASS_7.3-17        memoise_0.1        munsell_0.3
>>> plyr_1.7.1
>>>  [9] proto_0.3-9.2      RColorBrewer_1.0-5 reshape2_1.2.1
>>> scales_0.2.0
>>> [13] stringr_0.6
>>>
>>>
>>>
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>
> INSTITUTO DE BIOMECÁNICA DE VALENCIA
> Universidad Politécnica de Valencia • Edificio 9C
> Camino de Vera s/n • 46022 VALENCIA (ESPAÑA)
> Tel. +34 96 387 91 60 • Fax +34 96 387 91 69
> www.ibv.org
>
>  Antes de imprimir este e-mail piense bien si es necesario hacerlo.
> En cumplimiento de la Ley Orgánica 15/1999 reguladora de la Protección
> de Datos de Carácter Personal, le informamos de que el presente mensaje
> contiene información confidencial, siendo para uso exclusivo del
> destinatario arriba indicado. En caso de no ser usted el destinatario
> del mismo le informamos que su recepción no le autoriza a su divulgación
> o reproducción por cualquier medio, debiendo destruirlo de inmediato,
> rogándole lo notifique al remitente.
>
> ______________________________________________
> R-help at 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
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-- 
Assistant Professor / Dobelman Family Junior Chair
Department of Statistics / Rice University
http://had.co.nz/