ggplot版本的dotplot

Question

想知道如何使用ggplot或巧妙的库函数来绘制这个点图。同时将mpg值标记在单个点上。

# Dotplot: Grouped Sorted and Colored
# Sort by mpg, group and color by cylinder 
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)

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Answer 1

通过快速清除行名作为列，您可以执行以下操作。

我们使用factor()作为颜色的美学，这样它就变得离散了/当看到这个外观时，您需要为scale和space指定"free_y"。

基座

library(tidyverse)
mtcars2 = rownames_to_column(mtcars, "car")
ggplot(mtcars2, aes(x = mpg, y = factor(car), color = factor(cyl))) + 
  geom_point(shape = 1) + 
  facet_grid(cyl ~ ., scales = "free_y", space = "free_y") + 
  theme_bw() + 
  theme(panel.grid = element_blank(),
        panel.grid.major.y = element_line(size=.1, color="grey90"),
        legend.position = "none") +
  ggtitle("Gas Milage for Car Models\ngrouped by cylinder") + 
  xlab("Miles Per Gallon") +
  ylab("")

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添加文本

ggplot(mtcars2, aes(x = mpg, y = factor(car), color = factor(cyl))) + 
  geom_point(shape = 1) + 
  geom_text(aes(label = mpg), colour = "grey40", size = 3, hjust = -0.3) + 
  facet_grid(cyl ~ ., scales = "free_y", space = "free_y") + 
  theme_bw() + 
  theme(panel.grid = element_blank(),
        panel.grid.major.y = element_line(size=.1, color="grey90"),
        legend.position = "none") +
  ggtitle("Gas Milage for Car Models\ngrouped by cylinder") + 
  xlab("Miles Per Gallon") +
  ylab("")

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您可能可以使用geom_label，但geom_text在这里工作得很好。

Answer 2

修改@zacdav的答案，使用forcats对每组中的点数排序

library(tidyverse)
library(forcats)
mtcars2 = rownames_to_column(mtcars, "car") %>%
    mutate(car_ordered = fct_reorder2(car, cyl, mpg, .desc = FALSE))

ggplot(mtcars2, aes(x = mpg, y = car_ordered, color = factor(cyl))) + 
    geom_point(shape = 1) + 
    geom_text(aes(label = mpg), colour = "grey40", size = 3, hjust = -0.3) + 
    facet_grid(cyl ~ ., scales = "free_y", space = "free_y") + 
    theme_bw() + 
    theme(panel.grid = element_blank(),
          panel.grid.major.y = element_line(size=.1, color="grey90"),
          legend.position = "none") +
    ggtitle("Gas Milage for Car Models\ngrouped by cylinder") + 
    xlab("Miles Per Gallon") +
    ylab("")

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