之前我们学习了ggplot绘制单变量，两个连续变量的图形，两个离散型变量。对于一个离散型变量，一个连续型变量，有很多作图方式，包括箱图，点图等等
• geom_boxplot() for box plot
• geom_violin() for violin plot
• geom_dotplot() for dot plot
• geom_jitter() for stripchart
• geom_line() for line plot
• geom_bar() for bar plot
今天我们介绍一下点图
library(ggplot2)data("ToothGrowth")ToothGrowth$dose <- as.factor(ToothGrowth$dose)head(ToothGrowth)
我们先建立一个图层，以dose为X轴，len为Y轴
e <- ggplot(ToothGrowth, aes(x = dose, y = len))主要函数及参数
• Key functions: geom_dotplot(), stat_summary()
• Key arguments to customize the plot: alpha, color, dotsize and fill.
基础用法
# Basic plote + geom_dotplot(binaxis = "y", stackdir = "center")# Change dotsize and stack ratioe + geom_dotplot(binaxis = "y", stackdir = "center",stackratio = 1.5, dotsize = 1.1)
添加统计值
stat_summary() 可以用来添加统计值
添加均值或中位数
# Add mean or median point: use fun = mean or fun = mediane + geom_dotplot(binaxis = "y", stackdir = "center") +stat_summary(fun = mean, geom = "point",shape = 18, size = 3, color = "red")
添加误差棒（均值加减标准差）
# Add mean points +/- SD# Use geom = "pointrange" or geom = "crossbar"e + geom_dotplot(binaxis = "y", stackdir = "center") +stat_summary(fun.data="mean_sdl", fun.args = list(mult=1),geom="pointrange", color = "red")
与箱图或者小提琴图合并
e + geom_boxplot() +geom_dotplot(binaxis = "y", stackdir = "center")e + geom_violin(trim = FALSE) +geom_dotplot(binaxis='y', stackdir='center')e + geom_violin(trim = FALSE) +geom_dotplot(binaxis='y', stackdir='center') +stat_summary(fun.data="mean_sdl", fun.args = list(mult=1),geom="pointrange", color = "red")
通过颜色区分分组
# 单一颜色e + geom_dotplot(binaxis='y', stackdir='center', color = "black",fill = "lightgray") + theme_minimal()# 改变轮廓颜色e + geom_dotplot(aes(color = dose), binaxis='y', stackdir='center',fill = "white") + theme_minimal()# 改变填充色e + geom_dotplot(aes(fill = dose), binaxis='y', stackdir='center') +theme_minimal()
多组点图
# 不同分组不同颜色e + geom_dotplot(aes(fill = supp), binaxis='y', stackdir='center')# 改变点的位置区分不同组e + geom_dotplot(aes(fill = supp), binaxis='y', stackdir='center',position=position_dodge(0.8))
改变颜色，增加箱图
# 改变颜色e + geom_dotplot(aes(fill = supp), binaxis='y', stackdir='center',position=position_dodge(0.8)) +scale_fill_manual(values=c("#999999", "#E69F00"))# 加箱图e + geom_boxplot(fill = "white") +geom_dotplot(aes(fill = supp), binaxis='y', stackdir='center')# 改变位置e + geom_boxplot(aes(fill = supp), position=position_dodge(0.8))+geom_dotplot(aes(fill = supp), binaxis='y', stackdir='center',position=position_dodge(0.8))
