R 标记点图

R 标记点图,r,R,给出以下示例和图表,如何绘制每个点旁边x轴的精确值 x <- mtcars[order(mtcars$mpg),] # sort by mpg x$cyl <- factor(x$cyl) # it must be a factor x$color[x$cyl==4] <- "red" x$color[x$cyl==6] <- "blue" x$color[x$cyl==8] <- "darkgreen" dotchart(x$mpg,labels=row.

给出以下示例和图表,如何绘制每个点旁边x轴的精确值

x <- mtcars[order(mtcars$mpg),] # sort by mpg
x$cyl <- factor(x$cyl) # it must be a factor
x$color[x$cyl==4] <- "red"
x$color[x$cyl==6] <- "blue"
x$color[x$cyl==8] <- "darkgreen"    
dotchart(x$mpg,labels=row.names(x),cex=.7,groups= x$cyl,
 main="Gas Milage for Car Models\ngrouped by cylinder",
   xlab="Miles Per Gallon", gcolor="black", color=x$color)

x您需要按类别排序,然后按x排序。然后你可以像里卡多建议的那样使用
text
,来解释类别之间的中断

x <- mtcars[order(-mtcars$cyl, mtcars$mpg),]
# sort by category, then by position within category

# As above
x$cyl <- factor(x$cyl) # it must be a factor
x$color[x$cyl==4] <- "red"
x$color[x$cyl==6] <- "blue"
x$color[x$cyl==8] <- "darkgreen"    
dotchart(x$mpg,labels=row.names(x),cex=.7,groups= x$cyl,
         main="Gas Milage for Car Models\ngrouped by cylinder",
         xlab="Miles Per Gallon", gcolor="black", color=x$color)

# Adding text
text(x = x$mpg,
     y = 1:nrow(x) + ifelse(x$cyl == "6", 2, ifelse(x$cyl == "4", 4, 0)),
     labels= x$mpg,
     cex = 0.5,
     pos = 4)

x尝试修改类似于
text的内容(x$mpg,labels=x$mpg,cex=0.6)