格木素图不显示Y轴上的所有因子:不完全图

Question

我使用来自xyplot()的Lattice来绘制由一个包含3列的dataframe定义的箭头: posi (数字)，from (字符)，to (字符)。问题是:有时，箭头超出了情节的规模。换句话说，绘图窗口不够大，无法可视化所有数据。

我试图显式地添加因子级别，但没有效果。这似乎是，如果更极端的水平(例如。"D")不存在于因子"df$from“中，那些不被计算为绘制绘图窗口。我看了ylim，但这仅限于数值。

我环顾四周，发现了很多关于重新定标，重新排序的斧头，但没有任何东西帮助我解决手头的问题。这个问题与@skan：How to plot segments or arrows in Lattice中的一个问题有关。

我的数据：

l <- c("A", "B", "C", "D")
df <- data.frame(posi = c(1, 2, 3, 4, 5), 
                 from = factor(c("A", "B", "C", "D", "A"), levels = l, ordered = TRUE),
                 to = factor(c("C", "D", "D", "C", "A"), levels = l, ordered = TRUE)
)

这一情节如预期的那样：

xyplot(from ~ posi , type="p", col="black",  data=df, pch=16, xlim = c(0,7), 
       panel = function(...){
         panel.dotplot(x = df$posi, y = df$from, col ="green", cex=1.6)
         panel.dotplot(x = (df$posi+1), y = df$to, col="black", cex=1.)
         panel.arrows(x0 = df$posi, y0 = df$from, x1 = df$posi+1, y1 = df$to, lwd=2, col="blue" )
       }
)

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当我只使用前3行，相同的数据框架，‘旧的’因子水平完好无损，绘图没有考虑到，稍后的"D“级别将是必要的。

## only first 3 rows, without element "D" in the factor df$from
df <- df[1:3, ] 

导致这一阴谋：

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我希望能够设置Y轴的限制，并希望得到任何帮助或提示。

Answer 1

可以通过在对xyplot的调用中指定"drop.unused.levels = FALSE“来避免这个问题。

library(lattice)

l <- c("A", "B", "C", "D")
df <- data.frame(posi = c(1, 2, 3, 4, 5), 
             from = factor(c("A", "B", "C", "D", "A"), levels = l, 
                           ordered = TRUE),
             to = factor(c("C", "D", "D", "C", "A"), levels = l, 
                         ordered = TRUE))


xyplot(from ~ posi , type="p", col="black",  data=df, pch=16, xlim = c(0,7), 
   panel = function(...){
     panel.dotplot(x = df$posi, y = df$from, col ="green", cex=1.6)
     panel.dotplot(x = (df$posi+1), y = df$to, col="black", cex=1.)
     panel.arrows(x0 = df$posi, y0 = df$from, x1 = df$posi+1, y1 = df$to, 
                  lwd=2, col="blue" )
   })

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df2 <- df[1:3,]
xyplot(from ~ posi , type="p", col="black",  data=df2, pch=16, xlim = c(0,7), 
   drop.unused.levels = FALSE,
   panel = function(...){
     panel.dotplot(x = df2$posi, y = df2$from, col ="green", cex=1.6)
     panel.dotplot(x = (df2$posi+1), y = df2$to, col="black", cex=1.)
     panel.arrows(x0 = df2$posi, y0 = df2$from, x1 = df2$posi+1, 
                  y1 = df2$to, lwd=2, col="blue" )
   })

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