Adding two y-axis titles on the same axis

Question

I am going to use a dataset and plot that came from a previous problem (Here):

dat <- read.table(text = "   Division Year OperatingIncome
1  A  2012           11460
2  B  2012            7431
3  C  2012           -8121
4  D  2012           15719
5  E  2012             364
6  A  2011           12211
7  B  2011            6290
8  C  2011           -2657
9  D  2011           14657
10 E  2011            1257
11 A  2010           12895
12 B  2010            5381
13 C  2010           -2408
14 D  2010           11849
15 E  2010             517",header = TRUE,sep = "",row.names = 1)

dat1 <- subset(dat,OperatingIncome >= 0)
dat2 <- subset(dat,OperatingIncome < 0)
ggplot() + 
    geom_bar(data = dat1, aes(x=Year, y=OperatingIncome, fill=Division),stat = "identity") +
    geom_bar(data = dat2, aes(x=Year, y=OperatingIncome, fill=Division),stat = "identity") +
    scale_fill_brewer(type = "seq", palette = 1)

It includes the following plot, which is where my question comes in:

My question: Is it possible for me to change the y-axis label to two different labels on the same side? One would say "Negative Income" and be on the bottom portion of the y-axis. The other would say "Positive Income" and be on the upper portion of the SAME y-axis.

I have seen this question asked in terms of dual y-axis for different scales (on opposite sides), but I specifically want this on the same y-axis. Appreciate any help - I also would prefer to use ggplot2 for this problem, if possible.

Answer 1

您可以annotate用来添加负收入和正收入的标签。要在绘图面板外添加文本，您需要关闭剪辑。以下是在绘图面板内部和外部添加文本的示例：

# Plot
p = ggplot() + 
  geom_bar(data = dat1, aes(x=Year, y=OperatingIncome, fill=Division),stat = "identity") +
  geom_bar(data = dat2, aes(x=Year, y=OperatingIncome, fill=Division),stat = "identity") +
  scale_fill_brewer(type = "seq", palette = 1) +
  geom_hline(yintercept=0, lwd=0.3, colour="grey20") +
  scale_x_continuous(breaks=sort(unique(dat$Year))) +
  theme_bw()

# Annotate inside plot area
p +  coord_cartesian(xlim=range(dat$Year) + c(-0.45,0.4)) + 
  annotate(min(dat$Year) - 0.53 , y=c(-5000,5000), label=c("Negative Income","Positive Income"), 
           geom="text", angle=90, hjust=0.5, size=3, colour=c("red","blue"))

# Annotate outside plot area by turning off clipping
pp = p + coord_cartesian(xlim=range(dat$Year) + c(-0.4,0.4)) + 
  annotate(min(dat$Year) - 0.9, y=c(-6000,10000), label=c("Negative Income","Positive Income"), 
           geom="text", angle=90, hjust=0.5, size=4, colour=c("red","blue")) +
  labs(y="")

pp <- ggplot_gtable(ggplot_build(pp))
pp$layout$clip <- "off"
grid.draw(pp)

您也可以cowplot按照@Gregor的建议使用。我之前没有尝试过，所以也许有比我在下面做的更好的方法，但是看起来您必须使用视口坐标而不是数据坐标来放置注释。

# Use cowplot
library(cowplot)

ggdraw() +
  draw_plot(p + labs(y=""), 0,0,1,1) +
  draw_label("Positive Income", x=0.01, y = 0.5, col="blue", size = 10, angle=90) +
  draw_label("Negative Income", x=0.01, y = 0.15, col="red", size = 10, angle=90) 

我意识到问题中的数据仅用于说明，但是对于这样的数据，折线图可能更易于理解：

library(dplyr)

ggplot(dat, aes(x=Year, y=OperatingIncome, color=Division)) + 
  geom_hline(yintercept=0, lwd=0.3, colour="grey50") +
  geom_line(position=position_dodge(0.2), alpha=0.5) +
  geom_text(aes(label=Division), position=position_dodge(0.2), show.legend=FALSE) +
  scale_x_continuous(breaks=sort(unique(dat$Year))) +
  theme_bw() +
  guides(colour=FALSE) +
  geom_line(data=dat %>% group_by(Year) %>% summarise(Net=sum(OperatingIncome), Division=NA),
            aes(x=Year, y=Net), alpha=0.4) +
  geom_text(data=dat %>% group_by(Year) %>% summarise(Net=sum(OperatingIncome), Division=NA),
            aes(x=Year, y=Net, label="Net"), colour="black") 

或者，如果需要条形图，则可能是这样的：

ggplot() + 
  geom_bar(data = dat %>% arrange(OperatingIncome) %>% 
             mutate(Division=factor(Division,levels=unique(Division))), 
           aes(x=Year, y=OperatingIncome, fill=Division), 
           stat="identity", position="dodge") +
  geom_hline(yintercept=0, lwd=0.3, colour="grey20") +
  theme_bw()