r - 使用 Sweave 的 for 循环中的多个绘图

Question

我在 Sweave 中的部分:

<<fig=TRUE,echo=FALSE>>=
for(i in 1:10) {
  plot(rep(i,10))
  dev.new()
}
@

在生成的 pdf 中，我只得到一个图(从第一次迭代开始)。我想打印所有 10 个图。我究竟做错了什么？我尝试替换 dev.new()与 frame()和 plot.new()但什么也没发生。

Answer 1

正如@rawr 建议的那样，最简单的解决方案是切换到 knitr (真的没有理由不这样做!)并输入 fig.keep="all"在您的代码块选项中(如果您切换到 knitr 您不再需要 fig=TRUE ...包括数字自动工作，fig.keep="none" 是 fig=FALSE 的类似物)

或者，如果您想坚持使用 Vanilla Sweave，请查看 Sweave manual页。 17:

A.9 Creating several figures from one figure chunk does not work

Consider that you want to create several graphs in a loop similar to

<<fig=TRUE>>
for (i in 1:4) plot(rnorm(100)+i)
@

This will currently not work, because Sweave allows only one graph per figure chunk. The simple reason is that Sweave opens a postscript device before executing the code and closes it afterwards. If you need to plot in a loop, you have to program it along the lines of

<<results=tex,echo=FALSE>>=
for(i in 1:4){
file=paste("myfile", i, ".eps", sep="")
postscript(file=file, paper="special", width=6, height=6)
plot(rnorm(100)+i)
dev.off()
cat("\\includegraphics{", file, "}\n\n", sep="")
}
@