r - 添加一栏，根据学生的情况和剩余名额分配愿望

Question

我想通过为每个学生(id)分配创建一个新列(UE)，根据他们的分类(顺序)按照以下顺序(C1，C2，C3)选择教学单元(u1到u3)之一，而检查每个作业中每个教学单元的剩余名额(u1=最多 2 个名额，u2= 最多 2 个名额，u3 = 最多 3 个名额)。

    id<-c(11, 12, 13, 14, 15,16)
    C1<-c("u1","u2","u2","u2","u1","u1")
    C2<-c("u3","u3","u3","u3","u3","u2")
    C3<-c("u2","u1","u1","u1","u2","na")
    order<-c(1,2,3,4,5,6)

d = data.frame(id, C1, C2, C3, order)

正确答案在下面的示例文件中。

id     C1 C2 C3 Ordre UE
1 11   u1 u3 u2     1 u1
2 12   u2 u3 u1     2 u2
3 13   u2 u3 u1     3 u2
4 14   u2 u3 u1     4 u3
5 15   u1 u3 u2     5 u1
6 16   u1 u2 na     6 without allocation  

但是，使用我的代码

d$UE <- ifelse(d$C1== "u1" & length(d$C1[d$C1=="u1"])<=2, 'u1',
    ifelse(d$C1== "u2" & length(d$C1[d$C1=="u2"])<=2, 'u2',
    ifelse(d$C1== "u3" & length(d$C1[d$C1=="u3"])<=3, 'u3', 
           
    ifelse(d$C2== "u1" & length(d$C2[d$C2=="u1"])<=2, 'u1',
    ifelse(d$C2== "u2" & length(d$C2[d$C2=="u2"])<=2, 'u2',
    ifelse(d$C2== "u3" & length(d$C2[d$C2=="u3"])<=3, 'u3',
    
    ifelse(d$C2== "u1" & length(d$C2[d$C2=="u1"])<=2, 'u1',
    ifelse(d$C2== "u2" & length(d$C2[d$C2=="u2"])<=2, 'u2',
    ifelse(d$C2== "u3" & length(d$C2[d$C2=="u3"])<=3, 'u3',              
           'without allocation')))))))))

我得到

id C1 C2 C3 order                 UE
1 11 u1 u3 u2     1 without allocation
2 12 u2 u3 u1     2 without allocation
3 13 u2 u3 u1     3 without allocation
4 14 u2 u3 u1     4 without allocation
5 15 u1 u3 u2     5 without allocation
6 16 u1 u2 na     6                 u2

我非常感谢你的帮助

Answer 1

您可以将最大数量的位置存储在一个单独的变量中，然后计算分配的位置:

# max places per unit
max_place <- c(u1 = 2, u2 = 2, u3 = 3)
# occupid places per unit
occ_place <- c(u1 = 0, u2 = 0, u3 = 0)

d$UE <- "without allocation"

# loop through your data.frame
for (i in seq_along(d)) {
  # loop over choices 
  for (j in c("C1", "C2", "C3")) {
    # check if there are places availble and allocate the unit
    if (occ_place[d[i,j]] < max_place[d[i, j]] & !is.na(d[i,j]) & d[i,j] != "na") {
      d$UE[i] <- d[i,j]
      occ_place[d[i,j]] <- occ_place[d[i,j]] + 1
      break
    }
  }
}

返回

  id C1 C2 C3 order                 UE
1 11 u1 u3 u2     1                 u1
2 12 u2 u3 u1     2                 u2
3 13 u2 u3 u1     3                 u2
4 14 u2 u3 u1     4                 u3
5 15 u1 u3 u2     5                 u1
6 16 u1 u2 na     6 without allocation