R help - Feb 2008 - Cannot save histogram picture when run from script

Hi,

I am faced with a strange problem. My picture file is empty when the
following statements were run from R script. But the picture file shows up
correctly, when the commands are individually run from Rgui.

png(file="histogram_correlation.png", bg = "white")
require(stats)
histogram( ~ height | voice.part, data = singer, nint = 17,
          endpoints = c(59.5, 76.5), layout = c(2,4), aspect = 1,
          xlab = "Height (inches)")
dev.off()

Thanks
Daren

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Ng Stanley <stanleyngkl <at> gmail.com> writes:
> I am faced with a strange problem. My picture file is empty when the
> following statements were run from R script. But the picture file shows up
> correctly, when the commands are individually run from Rgui.
> 
> png(file="histogram_correlation.png", bg = "white")
> require(stats)
> histogram( ~ height | voice.part, data = singer, nint = 17,
>           endpoints = c(59.5, 76.5), layout = c(2,4), aspect = 1,
>           xlab = "Height (inches)")
> dev.off()
> 
The FAQ of FAQs, but admittely confusing (I remember Douglas Bates calling
Deepayan in the middle of the night in India): lattice graphics must be printed
in this context. I usually do it in two steps:

p = histogram(...)
print(p,(add layout if required here))

Dieter