【问题标题】：How to add a single label to a stacked bar chart in GGplot2如何将单个标签添加到GGplot2中的堆叠条形图
【发布时间】：2018-04-25 16:19:11
【问题描述】：

我想在 GGplot2 的堆积条形图中添加一个数字标签。

我有以下代码：

   # Load the packages
library(dplyr)
library(readr)
library(tidyr)
library(ggplot2)
library(RColorBrewer)

# Create a data set called M
M <- structure(list(X1 = c("Diversity", "Endangerment", "Marketability", "Total"),
B1 = c(5.1, 4.9, 4.7, 4.6), B2 = c(3.5, 
3, 3.2, 3.1), B3 = c(1.4, 1.4, 1.3, 1.5), Petal.Width = c(7.1, 
4.7, 3.2, 5.1)), .Names = c("X1", "B1", "B2", "B3", "B4"), row.names = c(NA, 
4L), class = "data.frame")
M

# Plot the stacked bar 
P <- M %>% 
  gather(variable, value, -X1) %>% 
  filter(X1!="Total") %>% #Removes total variable
  group_by(variable) %>% 
  mutate(sum=sum(value)) %>% 
  ungroup() %>% 
  mutate(variable=reorder(variable, -sum)) %>% #Reorders the chart based on breed total score
  ggplot(aes(variable, value, fill=X1, width =.7)) +
  geom_col(col="black") + #Black border around the bars
  expand_limits(y = 0) +
  scale_y_continuous(limits = c(0,70), breaks=c(0,10,20, 30,40, 50,60, 70), expand = c(0.02, 0.02))+
  geom_text(aes(label = sum), vjust = -.25)+ #Here the text is added
  scale_fill_brewer(palette="Dark2") + #Changes the colour scale
  labs(x="Breed",
       y="Weighted score",
       fill="") +
  theme_bw() +
  theme(panel.grid.major = element_blank(),
        panel.grid.minor = element_blank(),
        legend.direction="vertical", legend.position=c(0.9, 0.85), 
        legend.text=element_text(size=11),
        legend.key = element_rect(size = 4),
        legend.key.size = unit(1.5, 'lines'))  # Ensures spacing between the different lines on the legend.
P

我想尝试在每个条形上方包含“总和”值。有什么想法我该怎么做吗？

【问题讨论】：

标签： r ggplot2 label stacked-chart

【解决方案1】：

回答

所以，我创建了另一个 data.frame，但使用 summarise 后，我们将只有 1 个总和值。

代码

df <- structure(list(X1 = c("Diversity", "Endangerment", "Marketability", "Total"),
                B1 = c(5.1, 4.9, 4.7, 4.6), B2 = c(3.5, 
                                                   3, 3.2, 3.1), B3 = c(1.4, 1.4, 1.3, 1.5), Petal.Width = c(7.1, 
                                                                                                             4.7, 3.2, 5.1)), .Names = c("X1", "B1", "B2", "B3", "B4"), row.names = c(NA, 
                                                                                                                                                                                      4L), class = "data.frame")

df %>% 
  gather(variable, value, -X1) %>% 
  filter(X1!="Total") %>% 
  group_by(variable) %>% 
  mutate(sum=sum(value)) %>% 
  ungroup() %>% 
  mutate(variable=reorder(variable, -sum)) ->df

df %>% 
  group_by(variable) %>% 
  summarise(max = max(sum)) ->df_max

df %>% 
  ggplot(aes(variable, value, width =.7)) +
  geom_col(col="black",aes(fill=X1)) + #Black border around the bars
  expand_limits(y = 0) +
  scale_y_continuous(limits = c(0,70), breaks=c(0,10,20, 30,40, 50,60, 70),         expand = c(0.02, 0.02))+
  geom_text(data = df_max,
        aes(label = max, y = max), vjust = -.25)+ #Here the text is added
  scale_fill_brewer(palette="Dark2") + #Changes the colour scale
  labs(x="Breed",
       y="Weighted score",
       fill="") +
  theme_bw() +
  theme(panel.grid.major = element_blank(),
    panel.grid.minor = element_blank(),
    legend.direction="vertical", legend.position=c(0.9, 0.85), 
    legend.text=element_text(size=11),
    legend.key = element_rect(size = 4),
    legend.key.size = unit(1.5, 'lines'))  # Ensures spacing between the different lines on the legend.

输出

【讨论】：

【解决方案2】：

如果我没有正确理解，你想要这样的东西：

mtcars %>% 
  group_by(cyl=as.factor(cyl) ) %>% 
  summarise(sum= sum(am)) %>% 
  ggplot(aes(cyl, sum))+
  geom_col(width = .5)+
  geom_text(aes(label = sum), vjust = -.25)+ #Here the text is added
  scale_y_continuous(limits = c(0,8.5))

【讨论】：

这几乎可行，但现在我得到了三批相同的总数（放置在堆叠条的每个类别中），而不是像上面的示例中那样在条的顶部有一个总数。有什么建议吗？
您能否提供一个可复制的数据示例？
我现在已经编辑了最初的帖子，并添加了一个可重现的例子 Vinicius。