r - 在 R 中，错误 "need at least one panel"是什么意思，如何解决？

Question

以下代码来自《R in Action》一书， list 16.1:

library(lattice)
attach(mtcars)

gear <- factor(gear, levels=c(3, 4, 5),
               labels=c("3 gears", "4 gears", "5 gears"))
cyl <- factor(cyl, levels=c(4, 6, 8),
              labels=c("4 cylinders", "6 cylinders", "8 cylinders"))

densityplot(~mpg,
            main="Density Plot",
            xlab="Miles per Gallon")

densityplot(~mpg | cyl,
            main="Density Plot by Number of Cylinders",
            xlab="Miles per Gallon")

bwplot(cyl ~ mpg | gear,main="Box Plots by Cylinders and Gears",
       xlab="Miles per Gallon", ylab="Cylinders")


xyplot(mpg ~ wt | cyl * gear,
       main="Scatter Plots by Cylinders and Gears",
       xlab="Car Weight", ylab="Miles per Gallon")

cloud(mpg ~ wt * qsec | cyl,
      main="3D Scatter Plots by Cylinders")

dotplot(cyl ~ mpg | gear,
        main="Dot Plots by Number of Gears and Cylinders",
        xlab="Miles Per Gallon")

splom(mtcars[c(1, 3, 4, 5, 6)],
      main="Scatter Plot Matrix for mtcars Data")

detach(mtcars)

我只能绘制第一个密度图和最后一个图 splom(...)。其余的图给我以下错误:

Error in limits.and.aspect(default.prepanel, prepanel = prepanel, have.xlim = have.xlim, : need at least one panel

这个错误是什么意思，我该如何解决？

我刚开始学习 R，我使用的版本是:

R version 3.1.0 (2014-04-10)
Platform: x86_64-w64-mingw32/x64 (64-bit)

locale:
[1] LC_COLLATE=English_Malaysia.1252  LC_CTYPE=English_Malaysia.1252   
[3] LC_MONETARY=English_Malaysia.1252 LC_NUMERIC=C                     
[5] LC_TIME=English_Malaysia.1252    

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] lattice_0.20-29

loaded via a namespace (and not attached):
[1] grid_3.1.0

编辑:

search() 的输出是:

 [1] ".GlobalEnv"        "mtcars"            "package:lattice"  
 [4] "package:stats"     "package:graphics"  "package:grDevices"
 [7] "package:utils"     "package:datasets"  "package:methods"  
[10] "Autoloads"         "package:base"  

Answer 1

我从 QuickR 复制代码时遇到了同样的问题.我通过将 gear 和 cyl 的级别从 int 更改为 string 来解决它，因为数据集中的值都是字符串。

gear.f<-factor(gear,levels=c("3gears","4gears","5gears"),
    labels=c("3gears","4gears","5gears")) 
cyl.f <-factor(cyl,levels=c("4cyl","6cyl","8cyl"),
    labels=c("4cyl","6cyl","8cyl"))