可重现示例：

require(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)
    
avg <- survfit(Surv(time = a, event = c) ~ 1, data = df)
survminer::ggsurvplot(
  avg,
  conf.int = FALSE,
  censor = FALSE,
  palette = "black",
  linetype = "dashed"      
)  

surv_b <- survfit(Surv(time = a, event = c) ~ b, data = df)
survminer::ggsurvplot(
  surv_b,
  conf.int = FALSE,
  censor = FALSE,
)  

surv_comb <- c(avg, surv_b)

survminer::ggsurvplot_combine(
  surv_comb, 
  data = df,
  combine = TRUE,
  censor = FALSE,
  legend = "right"
)

两条生存曲线分别绘制，没有错误，但是当我尝试合并它们时，我得到一个错误，即 *！$运算符对原子向量无效 *。我已经用is.atomic（）检查了几乎所有的东西，但我找不到问题的原因。有人能帮我找出这个问题吗？