在 R 的 geom_line 中添加标签

Question

我有两个非常相似的图，它们有两个 y 轴 - 一个条形图和一个线图：

代码：

sec_plot <- ggplot(data, aes_string (x = year, group = 1)) +
    geom_col(aes_string(y = frequency), fill = "orange", alpha = 0.5) +
    geom_line(aes(y = severity))  

但是，没有标签。我想获得条形图的标签以及线图的标签，例如：

如果只有 pone 单组，如何将标签添加到绘图中？有没有办法手动指定这个？直到知道我才找到可以通过在aes中指定标签来添加标签的选项

EXTENSION（后加）：

getSecPlot <- function(data, xvar, yvar, yvarsec, groupvar){

  if ("agegroup" %in% xvar) xvar <- get("agegroup")
  # data <- data[, startYear:= as.numeric(startYear)]

  data <- data[!claims == 0][, ':=' (scaled = get(yvarsec) * max(get(yvar))/max(get(yvarsec)),
                                     param  = max(get(yvar))/max(get(yvarsec)))]

  param <- data[1, param] # important, otherwise not found in ggplot

  sec_plot <- ggplot(data, aes_string (x = xvar, group = groupvar)) +
    geom_col(aes_string(y = yvar, fill = groupvar, alpha = 0.5), position = "dodge") +
    geom_line(aes(y = scaled,  color = gender)) +
    scale_y_continuous(sec.axis = sec_axis(~./(param), name = paste0("average ", yvarsec),labels = function(x) format(x, big.mark = " ", scientific = FALSE))) +
    labs(y = paste0("total ", yvar)) +
    scale_alpha(guide = 'none') + 
    theme_pubclean() +
    theme(legend.title=element_blank(), legend.background = element_rect(fill = "white"))
}

plot.ExposureYearly <- getSecPlot(freqSevDataAge, xvar = "agegroup", yvar = "exposure", yvarsec = "frequency", groupvar = "gender")
plot.ExposureYearly

如何在线图和条形图都按性别分开的图上做同样的事情？

Answer 1

这是一个可能的解决方案。我使用的方法是在 aes 内移动颜色和填充，然后使用 scale_*_identity 创建和格式化图例。
另外，我需要为严重性轴添加比例因子，因为 ggplot 不能很好地处理辅助轴。

data<-data.frame(year= 2000:2005, frequency=3:8, severity=as.integer(runif(6, 4000, 8000)))

library(ggplot2)
library(scales)

sec_plot <- ggplot(data, aes(x = year)) +
  geom_col(aes(y = frequency, fill = "orange"), alpha = 0.6) +
  geom_line(aes(y = severity/1000, color = "black")) +
  scale_fill_identity(guide = "legend", label="Claim frequency (Number of paid claims per 100 Insured exposure)", name=NULL) +
  scale_color_identity(guide = "legend", label="Claim Severity (Average insurance payment per claim)", name=NULL) +
  theme(legend.position = "bottom") +
  scale_y_continuous(sec.axis =sec_axis( ~ . *1, labels = label_dollar(scale=1000), name="Severity") ) +  #formats the 2nd axis
  guides(fill = guide_legend(order = 1),  color = guide_legend(order = 2))                                #control which scale plots first

sec_plot