用R绘制棒棒糖图

Lollipop是条形图/柱状图的一种，总体呈现效果比条形图/柱状图更加美观和易懂，一般我们用条形图展示如下：

换成棒棒糖图如下：

棒棒糖图绘制相对简单：

library(ggplot2)
library(ggthemes)
library(splines)
library(dplyr)

value <- abs(rnorm(10)) * 2
don <- data.frame(
  X = paste0("A", seq(1, 10)),
  value = value
)%>%
  mutate(x=factor(X, X))

don %>%
ggplot( aes(x=X, y=value) ) +
    geom_segment( aes(x=X ,xend=X, y=0, yend=value), color="grey") +
    geom_point(size=3, color="#69b3a2") +
    # 翻转
    # coord_flip() +
    theme_few() +
    theme(
      panel.grid.minor.y = element_blank(),
      panel.grid.major.y = element_blank(),
      legend.position="none"
    ) +
    xlab("") +
    ylab("lollipop plot")

一个简单的棒棒糖图就绘制好了，如果是简单的图形我们用棒棒糖图，反而图形的美观度不如条形图。但是如果我们需要展示成对的比较此时用哑铃图（可以看做棒棒糖图变种）是更加直观：

上图也是近两年CNS文章的标配，下面我们一步步用R来绘制上图：

library(ggplot2)
library(ggthemes)
library(splines)
library(dplyr)

value1 <- abs(rnorm(26)) * 2
don <- data.frame(
  #x=LETTERS[1:26], # 假如你有100个样本定义1~100个数即可，目的是后续做拟合线用
  x = seq(1, 26),
  value1 = value1,
  value2 = value1 + 3 + rnorm(26, sd = 1)
) %>%
  rowwise() %>%
  mutate(mymean = mean(c(value1, value2))) %>%
  arrange(mymean) %>%
  mutate(x = as.integer(x, x))


ggplot(don) +
  geom_segment(aes(
    x = x,
    xend = x,
    y = value1,
    yend = value2
  ),
  color = "grey",
  size = 1.5) +
  geom_point( # 添加第一个点
    aes(x = x, y = value1),
    group = 1,
    color = rgb(0.2, 0.7, 0.1, 0.8),
    size = 3
  ) +
  geom_smooth( # 添加拟合曲线
    aes(x = x, y = value1),
    linetype = 3,
    group = 1,
    method = "loess",
    formula = y ~ splines::ns(x),
    color = "LightGreen", # 设置拟合线的颜色
    fill = "LightGreen" # 设置填充色（置信区域）
  ) +
  geom_line(
    aes(x = x, y = value1),
    group = 1,
    color = rgb(0.2, 0.7, 0.1, 0.8),
    # 0 = blank, 1 = solid, 2 = dashed, 3 = dotted, 4 = dotdash, 5 = longdash, 6 = twodash
    linetype = 1
  ) +
  geom_point(aes(x = x, y = value2),# 添加第二个点
             color = rgb(0.7, 0.2, 0.1, 0.8),
             size = 3) +
  geom_smooth(
    aes(x = x, y = value2),
    group = 1,
    linetype = 3,
    method = "loess",
    formula = y ~ splines::ns(x),
    color = "RosyBrown1",
    fill = "RosyBrown1"
  ) +
  geom_line(
    aes(x = x, y = value2),
    group = 2,
    color = rgb(0.7, 0.2, 0.1, 0.8),
    linetype = 1
  ) +
  #coord_flip()+ # 如果需要翻转图形，请去掉此处注释
  theme_few() +
  xlab("") +
  ylab("Value of Y") + # 设置Y轴标题
  scale_x_discrete(limits = LETTERS[1:26]) # 最后将坐标轴换回我们原始的名称，（此处需要和开始seq的数量对应）

写在最后，所有的图形可视化的目的都是为了更加清楚的展示你的数据信息，使其更加直观！

参考资料：

1.https://www.data-to-viz.com/graph/lollipop.html