double geom_bar，如何获取每个条的值

Question

我在两个不同时间段（Y轴）上都有一个国家（X轴）的图表，因此每个国家/地区都加倍。我想查看每个栏的值。我使用了geom_text，但是我在同一行上得到了值，所以它们不在适当的位置。如何为这种类型的绘图使用geom_text？

Rcountry %>%
  gather("Type", "Value",-Country) %>%
  ggplot(aes(Country, Value, fill = Type)) +
  geom_bar(position = "dodge", stat = "identity") + 
  coord_flip()+
  theme_minimal()+scale_fill_grey()+
  theme(legend.position="bottom")+
  theme(legend.title = element_blank())+
  scale_fill_manual(values=c("darkslategray4", "darkslategrey"))+
  labs(x="Country", y="Stock of robots per thousands worker in '000")+
  geom_text(aes(label=c(X2010, X2018)), size=3.5)```

Thank you

Answer 1

library(ggplot2)
library(dplyr)

mtcars2 <- mtcars %>% 
  group_by(cyl, gear) %>% 
  summarise(mpg = mean(mpg)) %>% 
  ungroup()

ggplot(mtcars2, aes(x = factor(cyl), mpg, fill = factor(gear))) + 
  geom_bar(position = "dodge", stat = "identity") +
  theme_minimal() + 
  scale_fill_grey() +
  theme(legend.position="bottom")+
  theme(legend.title = element_blank())+
  labs(x="Country", y="Stock of robots per thousands worker in '000")+
  geom_text(aes(label = mpg), position = position_dodge(.9), size=3.5) +
  coord_flip()

由reprex package（v0.3.0）在2020-04-15创建