如何在ggplot R的范围内限制辅助y轴的比例？

Question

我想将次轴从 0 固定到 1，因为概率始终在 0 到 1 的范围内。但是，根据数据，如果最大回报 (y) 很高（如下图所示， 6%），那么次y轴的比例会超过1（因为它依赖于主y轴），这不是一个理想的演示情况。我应该如何限制辅助 y 轴的最大比例？

我听说ggplot 仍然不允许我们限制辅助轴的比例，但我不确定是否正确。是否有任何其他方法可以限制辅助 y 轴的比例，以便图表上显示的最大概率始终为 1 或小于 1，这取决于最大回报。请注意，代码中显示的 y 是返回值。

y <- c(0.01, -0.005, 0.06)
Month <- c("Jan", "Feb", "Mar")

dtf <- data.frame(Month, y)

require(reshape)
dtf2 <- melt(dtf)
dtf2[["sign"]] = ifelse(dtf2[["value"]] >= 0, "positive", "negative")
Probability <- c(0.4,0.22,0.54)

dtf2 <- data.frame(dtf2, Probability)

dtf2 %>>% ggplot() + 
  geom_bar(mapping = aes(x=Month, y=value, fill = sign), stat ="identity", width = 0.75)+
  geom_point(mapping = aes(x=Month, y=Probability/20-0.025), size = 2.5, color="blue")+
  geom_line(mapping = aes(x=Month, y=Probability/20-0.025, group = 1), color = "blue", size = 1)+
  geom_hline(yintercept=0)+
  geom_text(aes(x=Month, y=value, label = paste(y * 100,"%"), vjust = ifelse(y >= 0, -0.5, 1.2)), hjust = 0.5)+
  ylab("\nReturn")+
  theme(axis.text.x = element_text(face = "bold", size=11),
        axis.text.y = element_text(face = "bold"),
        axis.title.x=element_blank(),
        legend.position = "none",
        plot.title = element_text(hjust = 0.5),
        plot.subtitle = element_text(hjust = 0.5))+
  theme(panel.background = element_blank(),
        axis.ticks.x = element_blank()) +
  theme(axis.line.y = element_line(color="black", size = 0.5))+
  scale_y_continuous(labels=scales::percent, sec.axis = sec_axis(~(. + 0.025)*20, name = "Probability\n" ))+
  scale_fill_manual(values = c("positive" = "black", "negative" = "red"))

如果回报较低，我希望辅助 y 轴的最大比例始终为 1 或小于 1。请给点建议，谢谢！

Answer 1

library(tidyverse)
library(rashape2)
y <- c(0.01, -0.05, 0.06)
Month <- c("Jan", "Feb", "Mar")
dtf <- data.frame(Month, y) 
require(reshape)
dtf2 <- melt(dtf)
dtf2[["sign"]] = ifelse(dtf2[["value"]] >= 0, "positive", "negative")
Probability <- c(0.4,0.22,0.54)
yrange <-max(y)- min(y) 
ymin <- min(y)
dtf2 <- data.frame(dtf2, Probability) 

dtf2 %>%  ggplot() + 
  geom_bar(mapping = aes(x=Month, y=value, fill = sign), stat ="identity", width  = 0.75)+
  geom_point(mapping = aes(x=Month, y=Probability*yrange+ymin), size = 2.5,  color="blue") +
  geom_line(mapping = aes(x=Month, y=Probability*yrange+ymin, group = 1), color = "blue", size = 1)+
  geom_hline(yintercept=0)+
  geom_text(aes(x=Month, y=value, label = paste(y * 100,"%"), vjust = ifelse(y >= 0, -0.5, 1.2)), hjust = 0.5)+
  ylab("\nReturn")+
  theme(axis.text.x = element_text(face = "bold", size=11), axis.text.y = element_text(face = "bold"),
    axis.title.x=element_blank(),
    legend.position = "none",
    plot.title = element_text(hjust = 0.5),
    plot.subtitle = element_text(hjust = 0.5))+
  theme(panel.background = element_blank(),
    axis.ticks.x = element_blank()) +
  theme(axis.line.y = element_line(color="black", size = 0.5))+
  scale_y_continuous(labels=scales::percent, sec.axis = sec_axis(~(. -ymin)/yrange, name = "Probability\n", breaks = c(0,0.5,1)))+
  scale_fill_manual(values = c("positive" = "black", "negative" = "red"))