R help - Mar 2008 - qplot (ggplot2) faceting histogram with missing values

Hi,
I've run into a difficulty with qplot function (in the ggplot2  
package). I can facet histograms even when the faceting variable  
contains missing values, but only so long as the faceting variable is  
not a factor.

Example:

y1 <- rnorm(10)
x1 <- c(rep(1,5), rep(2,4), NA)
x2 <- factor(c(rep(1,5), rep(2,4), NA))
library(ggplot2)
qplot(y1, geom = "histogram", facets = x1 ~.)# this works
qplot(y1, geom = "histogram", facets = x2 ~.)# this doesn't work
Error in if (is.null(data) || nrow(data) == 0) return() :
   missing value where TRUE/FALSE needed

This is with ggplot2_0.5.7, R version 2.6.2, on OS X 10.5.2.

Not that this is terribly hard to work around, for example by  
converting the factor to a vector or simply deleting missing values.  
I'm mostly just curious about why it doesn't work.

By the way, I really like ggplot2, though I must admit I'm struggling  
a bit to understand how it really works (I mostly use qplot). Thanks  
for making this great package available.
-Ista

Hi Ista,

That's a bug, and will be fixed in the next version (hopefully to be
released in the next couple of days)

Hadley

On Mon, Mar 3, 2008 at 7:10 PM, Ista Zahn <istazahn at gmail.com>
wrote:
> Hi,
>  I've run into a difficulty with qplot function (in the ggplot2
>  package). I can facet histograms even when the faceting variable
>  contains missing values, but only so long as the faceting variable is
>  not a factor.
>
>  Example:
>
>  y1 <- rnorm(10)
>  x1 <- c(rep(1,5), rep(2,4), NA)
>  x2 <- factor(c(rep(1,5), rep(2,4), NA))
>  library(ggplot2)
>  qplot(y1, geom = "histogram", facets = x1 ~.)# this works
>  qplot(y1, geom = "histogram", facets = x2 ~.)# this doesn't
work
>  Error in if (is.null(data) || nrow(data) == 0) return() :
>    missing value where TRUE/FALSE needed
>
>  This is with ggplot2_0.5.7, R version 2.6.2, on OS X 10.5.2.
>
>  Not that this is terribly hard to work around, for example by
>  converting the factor to a vector or simply deleting missing values.
>  I'm mostly just curious about why it doesn't work.
>
>  By the way, I really like ggplot2, though I must admit I'm struggling
>  a bit to understand how it really works (I mostly use qplot). Thanks
>  for making this great package available.
>  -Ista
>
>  ______________________________________________
>  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
>  and provide commented, minimal, self-contained, reproducible code.
>


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