R 在堆叠条形图上绘制标签

我有需要放入堆栈条形图的数据，但当我添加计数的标签时，一些标签在类别上方，一些在类别下方。我试图修改geom_文本函数的位置参数，但没有效果

下面是一个可复制的示例，显示了该类别上方“下方”类别座位的标签以及酒吧内“上方”类别座位的标签

library(tidyverse)

data.frame(AgeGroup = sample(c(rep("Over",10),"Under"), 6000, replace = TRUE),
DueDate = sample( 
         seq( as.Date("2015-01-01"), 
              as.Date("2015-06-30"), by="1 month") ,  
         6000,replace = TRUE),
             stringsAsFactors = TRUE) %>%
group_by(AgeGroup,DueDate) %>%
  tally() %>% ungroup %>% 
  ggplot() +
  geom_bar(aes(x=DueDate, y=n, fill = AgeGroup),stat = "identity") +
  geom_text(aes(x=DueDate, y=n
            ,label = prettyNum(n,big.mark = ","))
        , vjust = 0,  size = 2) +
  scale_y_continuous(labels = scales::comma) +
  theme_bw() +
  labs(title="Where are the labels")

下面是输出图表。

---

只需使用

n/2

作为

geom_text（）

的

y

位置，它将始终落在条形图的“内部”：

编辑：该快速解决方案仅适用于您的特定示例。如果每个栏有两个以上的类别，或者如果值分布更均匀，它将不会飞行。i、 e:

set.seed(999)
data.frame(Direction = sample(rep(c("South", "West", "East", "North")), 6000, replace = TRUE),
           DueDate = sample( 
               seq( as.Date("2015-01-01"), 
                    as.Date("2015-06-30"), by="1 month") ,  
               6000,replace = TRUE),
           stringsAsFactors = TRUE) %>%
    group_by(Direction, DueDate) %>%
    tally() %>% 
    ungroup %>%
    arrange(desc(Direction)) %>% 
    group_by(DueDate) %>% 
    mutate(pos = cumsum(n) - n/2) %>% 
    ggplot() +
    geom_bar(aes(x=DueDate, y=n, fill = Direction),stat = "identity") +
    geom_text(aes(x=DueDate, y=pos, label = prettyNum(n,big.mark = ","))
              , vjust = 0,  size = 2) +
    scale_y_continuous(labels = scales::comma) +
    theme_bw() +
    labs(title="Where are the labels")

因此，这里有一个通用解决方案，它向数据帧（

arrange（desc（Direction））%%>%groupby（DueDate）%%>%mutate（pos=cumsum（n）-n/2）

）添加一个“position”列，用于

geom_text（）

，并将标签精确放置在它们所属的位置：

set.seed(999)
data.frame(Direction = sample(rep(c("South", "West", "East", "North")), 6000, replace = TRUE),
           DueDate = sample( 
               seq( as.Date("2015-01-01"), 
                    as.Date("2015-06-30"), by="1 month") ,  
               6000,replace = TRUE),
           stringsAsFactors = TRUE) %>%
    group_by(Direction, DueDate) %>%
    tally() %>% 
    ungroup %>%
    arrange(desc(Direction)) %>% 
    group_by(DueDate) %>% 
    mutate(pos = cumsum(n) - n/2) %>% 
    ggplot() +
    geom_bar(aes(x=DueDate, y=n, fill = Direction),stat = "identity") +
    geom_text(aes(x=DueDate, y=pos, label = prettyNum(n,big.mark = ","))
              , vjust = 0,  size = 2) +
    scale_y_continuous(labels = scales::comma) +
    theme_bw() +
    labs(title="Where are the labels")

---

需要注意的是：使用

sample

导出的数据不能严格复制，除非您先使用

set.seed（）

。

set.seed(999)
data.frame(Direction = sample(rep(c("South", "West", "East", "North")), 6000, replace = TRUE),
           DueDate = sample( 
               seq( as.Date("2015-01-01"), 
                    as.Date("2015-06-30"), by="1 month") ,  
               6000,replace = TRUE),
           stringsAsFactors = TRUE) %>%
    group_by(Direction, DueDate) %>%
    tally() %>% 
    ungroup %>%
    arrange(desc(Direction)) %>% 
    group_by(DueDate) %>% 
    mutate(pos = cumsum(n) - n/2) %>% 
    ggplot() +
    geom_bar(aes(x=DueDate, y=n, fill = Direction),stat = "identity") +
    geom_text(aes(x=DueDate, y=pos, label = prettyNum(n,big.mark = ","))
              , vjust = 0,  size = 2) +
    scale_y_continuous(labels = scales::comma) +
    theme_bw() +
    labs(title="Where are the labels")