R 如何快速创建所有组合字符串值的变量​；数据帧中某个特定列的？

temp_day是数据帧，它有十亿行

Height_classify <- data.frame(color = c('red', 'orange', 'yellow', 'green', 'blue', 'indigo', 'violet'),
                                  min = c(0, 100,300,500,1000,2000,5000),
                                  max = c(100,300,500,1000,2000,5000,8000))

make_code <- function(temp_day, h_class){
  temp_class <- Height_classify %>% filter(color == h_class)
  min_godo <- temp_class[1,2]
  max_godo <- temp_class[1,3]
  temp_day_hight <- temp_day %>% filter(AltitudeActual_m >= min_godo & AltitudeActual_m < max_godo)
  polys <- stri_c("polys_", temp_class[1,1], " = [")
  hight_flight <- as.data.frame(table(unlist(temp_day_hight$mdH_CallSign)), stringsAsFactors = F)

  for (sFlight in hight_flight$Var1){

    temp_day_hight_flight <- temp_day_hight %>% filter(mdH_CallSign == sFlight)

    if (nrow(temp_day_hight_flight) >1){

      polys <- stri_c(polys, "[")

      for (i in 1:nrow(temp_day_hight_flight)){

        polys <- stri_c(polys, temp_day_hight_flight$coord[i]) 
        if (i < nrow(temp_day_hight_flight)){
          polys <- stri_c(polys, ", ")
        } else {
          polys <- stri_c(polys, "], ")
        }

      } # for i
    } # if
  }# for sFlight
  polys <- substr(polys, 1, nchar(polys)-2)
  polys <- stri_c(polys, "]\n\n")

  return(polys)
}

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我的英语不好。请理解这句话是否有误。如果没有原始数据帧，很难提供解决方案，但对于大型数据帧（>10万行）上的操作，执行类似于嵌套for循环的操作将非常低效，更不用说10亿行了。如果您的数据集是

polys <- stri_c(polys, temp_day_hight_flight$coord[i])