通过while循环或Reduce建立多级员工经理关系，仅限base R

# 创建一个员工经理关系的数据框
employees <- data.frame(
  employee = c("A", "B", "C", "D", "E"),
  manager = c("B", "C", "D", "E", NA)
)

# 建立多级员工经理关系
while(any(is.na(employees$manager))) {
  for(i in 1:nrow(employees)) {
    if(is.na(employees$manager[i])) {
      manager <- employees$employee[employees$manager == employees$employee[i]]
      if(length(manager) > 0) {
        employees$manager[i] <- manager
      }
    }
  }
}

# 打印结果
print(employees)

# 创建一个员工经理关系的数据框
employees <- data.frame(
  employee = c("A", "B", "C", "D", "E"),
  manager = c("B", "C", "D", "E", NA)
)

# 定义一个函数，用于建立员工经理关系
build_hierarchy <- function(employees, employee) {
  manager <- employees$employee[employees$manager == employee]
  if(length(manager) > 0) {
    employees$manager[employees$employee == employee] <<- manager
  }
  employees
}

# 建立多级员工经理关系
result <- Reduce(build_hierarchy, employees$employee, init = employees)

# 打印结果
print(result)