如何在sapply生成的ggplot分图中设置多条竖线的颜色与线型

你可以通过以下两种方式实现每条垂直线独立设置颜色、线型、粗细： #

方法1：调整循环逻辑适配多参数 #

保留原有循环思路，改用mapply同时传入线位置和对应样式参数：

library(gridExtra)
library(grid)
library(lattice)
library(ggplot2)
library(dplyr)

# 统一配置垂直线参数，顺序一一对应
vertical.lines <- c(1990,1991)
line_lty <- c(3,1)
line_color <- c("blue","red")
line_lwd <- c(0.5,0.5)

df1 %>%
  filter(isocode == "KOR") %>%
  select(year,rgdpe, rgdpo, avh, emp, hc) %>%
  tidyr::gather(predictor, value, -year)%>%
  ggplot() + 
  geom_line(aes(year, value))+ 
  facet_wrap(~predictor, scales = "free")+ 
  labs(x = NULL, y = NULL, top = "Title of the Chart",
  bottom = textGrob(
    "Data source: World Bank",
    gp = gpar(fontface = 3, fontsize = 9),
    hjust = 1,x = 1)) +
  # mapply逐组传入参数生成对应样式的垂直线
  mapply(function(xint, lt, col, lw) geom_vline(xintercept = xint, lty = lt, color = col, lwd = lw),
         vertical.lines, line_lty, line_color, line_lwd)

方法2：数据框管理垂直线参数（更推荐） #

把垂直线的所有参数整合到独立数据框中，通过映射实现样式自定义，后续增删线、调整参数更便捷：

library(gridExtra)
library(grid)
library(lattice)
library(ggplot2)
library(dplyr)

# 构建垂直线参数表，每条线对应一行
vline_df <- data.frame(
  xint = c(1990, 1991),
  lty = c(3, 1),
  color = c("blue", "red"),
  lwd = c(0.5, 0.5)
)

df1 %>%
  filter(isocode == "KOR") %>%
  select(year,rgdpe, rgdpo, avh, emp, hc) %>%
  tidyr::gather(predictor, value, -year)%>%
  ggplot() + 
  geom_line(aes(year, value))+ 
  # 直接使用参数表中的配置，无需映射避免生成多余图例
  geom_vline(data = vline_df, aes(xintercept = xint), 
             linetype = vline_df$lty, color = vline_df$color, linewidth = vline_df$lwd)+
  facet_wrap(~predictor, scales = "free")+ 
  labs(x = NULL, y = NULL, top = "Title of the Chart",
  bottom = textGrob(
    "Data source: World Bank",
    gp = gpar(fontface = 3, fontsize = 9),
    hjust = 1,x = 1))

补充说明 #

• 如果需要为垂直线生成图例，可将linetype/color/linewidth参数放入aes()内，配合scale_*_manual()系列函数自定义图例样式即可
• 两种方法均适配任意数量的垂直线，只需对应补充参数列表/参数表行即可

内容的提问来源于stack exchange，提问作者jck21