设置linetype时survminer::ggsurvplot_combine图例重复问题求助

使用survminer包的ggsurvplot_combine绘制组合生存曲线时，为区分平均曲线与分组曲线设置linetype参数（将平均曲线设为虚线），会导致图例重复显示颜色和线型两个分组；注释掉linetype参数后图例显示正常，但无法区分曲线样式。需要保留指定线型样式，同时仅显示一个颜色图例。

核心是手动控制ggplot的图例逻辑：关闭自动生成的线型图例，同时让颜色图例关联对应的线型样式，确保图例与曲线样式一致。具体步骤：

1. 先运行原代码生成基础绘图对象；
2. 通过ggplot2的guides()函数关闭线型图例；
3. 用override.aes参数在颜色图例中指定每个标签对应的线型，保证图例样式与曲线匹配。

require(survival)  # 修正原代码中的大小写错误，应为小写survival
require(survminer)
require(ggplot2)

set.seed(42)

a <- c(32,291,545, 44,3,792,352, 20,615,169, 61,156, 88,863,255, 33,132,5,
       63,8,964,831, 55,133, 12, 54,261,867, 17, 12,699,233,251,446, 43,223, 
       374, 75, 34, 69,120, 84,134,8,806,8, 48, 86,211, 2436, 61, 81, 87, 12, 
       838, 34, 17,141, 44,155,128,6, 29, 16, 16, 34,130,430,325, 41, 28, 53,
       32,291,545, 44,3,792,352, 20,615,169, 61,156, 88,863,255, 33,132,5,
       63,8,964,831, 55,133, 12, 54,261,867, 17, 12,699,233,251,446, 43,223,
       86, 54,3,630, 93,699, 25,746,6, 46, 22, 60,395,402,151, 26, 38,125, 
       75, 34, 69,120, 84,134,8,806,8, 48, 86,211, 2436, 61,
       191, 49, 59,6, 34, 56,2, 96, 422, 45, 70)

b <- sample(c("Alpha", "Beta", "Gamma"), length(a), replace = T)
c <- sample(0:1, length(a), replace = T)
df <- data.frame(a, b, c)

df$b <- factor(df$b, levels = c("Alpha", "Beta", "Gamma"))
avg <- survfit(Surv(time = a, event = c) ~ 1, data = df)
surv_b <- survfit(Surv(time = a, event = c) ~ b, data = df)
surv_comb <- list(surv_b, avg)

# 生成基础绘图对象
p <- survminer::ggsurvplot_combine(
  surv_comb, 
  data = df,
  combine = TRUE,
  censor = FALSE,
  legend = "right",
  palette = c("orange", "steelblue", "seagreen", "black"),
  linetype = c(rep("solid",3), "dashed"),
  legend.title = element_blank(),
  legend.labs = c(levels(df$b), "avg")
)

# 修改ggplot对象，合并图例
p$plot + 
  guides(
    linetype = "none",  # 关闭线型图例
    color = guide_legend(
      override.aes = list(linetype = c(rep("solid",3), "dashed"))  # 让颜色图例显示对应线型
    )
  )

• 原代码中require(Survival)为拼写错误，需改为require(survival)；
• override.aes中的线型顺序必须与legend.labs的标签顺序完全对应，保证图例样式和曲线一致。

内容的提问来源于stack exchange，提问作者Reader 123