简介

棒棒糖图（Lollipop chart）是柱形图的变种，简单来看就是圆形标点（marker）和连接到 x 轴的线组成的一种图形。

一个分组变量

data <- mpg %>%
 group_by( manufacturer) %>% 
 summarise(count = n())

# 设置连线的起点Y坐标为0
data$ymin <- rep(0, 15)

ggplot(data = data) + geom_point(aes(x = manufacturer, 
 y = count),size = 5) +
 geom_segment(aes(x = manufacturer, y = ymin,
 xend = manufacturer, yend = count)) +
# 设置y轴从0开始
 scale_y_continuous(expand = c(0,0))+
# 由于x轴名字有重叠，旋转坐标轴变成横向
 coord_flip() + 
 theme(panel.background = element_blank(), # 去掉背景格子
# 显示x平行网格线
 panel.grid.major.x = element_line(colour = "black"), 
# 显示x轴坐标
 axis.line.x = element_line(colour = "black"),
 axis.title.y = element_blank())

Lollipop Chart.png

分组中再分组

data <- mpg %>%
 group_by( manufacturer, cyl) %>% 
 summarise(count = n())
data$ymin <- rep(0, times = 32)
# 将两个分组信息合并生成新的分组，此时
data$group <- paste(data$manufacturer, data$cyl, sep="_")

theme <- theme(panel.background = element_blank(), # 去掉背景格子
 # 显示x平行网格线
 panel.grid.major.x = element_line(colour = "black"), 
 # 显示x轴坐标
 axis.line.x = element_line(colour = "black"),
 axis.title.y = element_blank())


ggplot(data = data) + geom_point(aes(x = group, y = count, 
 color = factor(cyl)), 
 size = 5) +
 geom_segment(aes(x = group, y = ymin,
 xend = group, yend = count)) +
 scale_y_continuous(limits =c(0, 25) ,expand = c(0,0))+
 coord_flip() + theme

Lollipop_group.png

但x轴的labels就变成了合并后的文字，解决办法：

1.修改x轴信息

data <- mpg %>%
 group_by( manufacturer, cyl) %>% 
 summarise(count = n())
data$ymin <- rep(0, times = 32)
as.integer()
data$index <- as.integer(rownames(data))

theme <- theme(panel.background = element_blank(), # 去掉背景格子
 # 显示x平行网格线
 panel.grid.major.x = element_line(colour = "black"), 
 # 显示x轴坐标
 axis.line.x = element_line(colour = "black"),
 axis.title.y = element_blank())


ggplot(data = data) + geom_point(aes(x = index, y = count, 
 color = factor(cyl)), 
 size = 5) +
 geom_segment(aes(x = index, y = ymin,
 xend = index, yend = count)) +
 scale_y_continuous(limits =c(0, 25) ,expand = c(0,0)) + 
# 修改坐标轴信息
 scale_x_continuous(breaks = data$index, 
 labels = data$manufacturer) +
 coord_flip() + theme

2.对分组变量添加label信息

data <- mpg %>%
 group_by( manufacturer, cyl) %>% 
 summarise(count = n())
data$ymin <- rep(0, times = 32)

data$manufacturer <- factor(as.integer(rownames(data)), 
 labels = data$manufacturer)

theme <- theme(panel.background = element_blank(), # 去掉背景格子
 # 显示x平行网格线
 panel.grid.major.x = element_line(colour = "black"), 
 # 显示x轴坐标
 axis.line.x = element_line(colour = "black"),
 axis.title.y = element_blank())


ggplot(data = data) + geom_point(aes(x = manufacturer, y = count, 
 color = factor(cyl)), 
 size = 5) +
 geom_segment(aes(x = manufacturer, y = ymin,
 xend = manufacturer, yend = count)) +
 scale_y_continuous(limits =c(0, 25) ,expand = c(0,0)) + 
 coord_flip() + theme

3.structure() - Attributes信息

所有对象都可以具有任意其他属性。可以将它们视为该列表和命名列表构成的数据框。可以使用attr()单独访问属性，也可以使用attribute()一次访问所有属性列表。而structure()函数是R中给对象赋予Attributes的函数。

names, character vector of element names
labels
class, used to implement the S3 object system, described in the next section
dim, used to turn vectors into high-dimensional structures

data <- mpg %>%
 group_by( manufacturer, cyl) %>% 
 summarise(count = n())
data$ymin <- rep(0, times = 32)

data$index <- fct_inseq(rownames(data))
# 添加Attributes - 也是labels
labels <- structure(data$manufacturer, 
 labels = data$index)
theme <- theme(panel.background = element_blank(), # 去掉背景格子
 # 显示x平行网格线
 panel.grid.major.x = element_line(colour = "black"), 
 # 显示x轴坐标
 axis.line.x = element_line(colour = "black"),
 axis.title.y = element_blank())


ggplot(data = data) + geom_point(aes(x = index, y = count, 
 color = factor(cyl)), 
 size = 5) +
 geom_segment(aes(x = index, y = ymin,
 xend = index, yend = count)) +
 scale_y_continuous(limits =c(0, 25) ,expand = c(0,0)) +
 scale_x_discrete(labels = labels) +
 coord_flip() + theme