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.weyla...@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.derosa...@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 >> >> >> >> 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@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 >> and provide commented, minimal, self-contained, reproducible code. 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@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 and provide commented, minimal, self-contained, reproducible code.
