安装pixmap包,
>library(pixmap)
>mtrush1 <- read.pnm("mtrush1.pgm")
提示:
Error in file(file, open = "rb") : cannot open the connection
In addition: Warning message:
In file(file, open = "rb") :
cannot open file 'mtrushl.pgm': No such file or directory
请问mtrush1.pgm不在pixmap包中吗?如果该图片不在此包中,我该如何实现《R语言编程艺术》pg53的这个例子?