R：从列表中随机选择项目

Question

我正在使用 R 编程语言。我想创建一个问题：

有4个人 : "person 1", "person 2", "person 3" ,"person 4"
有食品清单："pizza", "apples", "tacos", "ice cream", "grapes", "olives", "sushi", "chocolate", "cake", "nachos", "pasta", "cookies", "popcorn", "soup"
一年中有几天:1 to 365

在这个问题中，人员列表是随机排序的。此列表的顺序决定谁先“选择”。

根据名单的顺序，名单开头的人将被分配4个随机号码：

Rand_1_1 (Person 1, First Random Number) : 第一个随机数将决定第一个人的“食物”数量允许选择（例如 3）
Rand_1_2 (Person 1, Second Random Number) : 第二个随机数将决定第一个人选择哪些“食物”与“Rand_1_1”对应的“食品”数量（例如“炸玉米饼”、“玉米片”、“汤”）
Rand_1_3（人1，第三个随机数）：第三个随机数将决定该天的天数第一人称
Rand_1_4（第一个人，第四个随机数）：第四个随机数决定第一个人的天数（例如，第 1 个人可能被指定为“41 到 160”天）。

这是为所有人完成的随机数分配过程：Rand_1_1、Rand_1_2、Rand_1_3、Rand_1_4、Rand_2_1, Rand_2_2, Rand_2_3, Rand_2_4, Rand_3_1, Rand_3_2, Rand_3_3, Rand_3_4, Rand_4_1 , Rand_4_2, Rand_4_3, Rand_4_4

但是，有一个逻辑约束:

“人”不能选择之前的“人”已经选择的“食品”（例如，如果第 1 人 selected 在第 2 人之前选择，如果第 1 个人选择了“披萨”，那么第 2 个人就不能选择“披萨”）
一个“人”不能选择之前“人”已经选择的“天数范围”
4个人都选完后，有可能可以保留一些“食物”和一些“日期范围” unselected。另一方面，假设如果第一个人选择第一个并且他碰巧 select 所有的“食物”——那么当然，其他人将没有“食物”。同样的逻辑适用于“日期范围”。

现在，我正在尝试在 R 中编写代码：

首先，我加载了库：

#load libraries

library(dplyr)
library(gtools)

其次，我创建的数据：

#create data

#variable 1: days of the year 

days <- 1:365

#variable 2 : food

food <- c("pizza", "apples", "tacos", "ice cream", "grapes", "olives", "sushi", "chocolate", "cake", "nachos", "pasta", "cookies", "popcorn", "soup")
food_data <- data.frame(food)
food_data$id <-  1:nrow(food_data)

# people 
people <- c("person 1", "person 2", "person 3" ,"person 4")

第三，我创建了人们选择的顺序：

# randomize order of people : this decides the order of who picks "days" and "food"

set.seed(123)

order_of_people = permute(people)

# in this example, "person 3" will pick first, "person 4" will pick second, "person 1" will pick third and "person 2" will pick last

order_of_people
[1] "person 3" "person 4" "person 1" "person 2"

我的问题： 我知道如何为每个人分配一个随机数，但我不知道如何分配随机数以符合逻辑约束。例如：

#choices for person 3 (according to the random seed, person 3 will pick 5 food items)

set.seed(120)

dim = dim(food_data)

#number of items selected by person 3

Rand_3_1 <- sample.int(dim[1], 1)

#which food items selected by person 3 (corresponding to the food_id : "3, 9, 6, 7, 4")
set.seed(120)

Rand_3_2 = c( sample.int(dim[1], 1), sample.int(dim[1], 1), sample.int(dim[1], 1),  sample.int(dim[1], 1), sample.int(dim[1], 1))

#which days selected by person 3 (according to this random seed, "65 to 87")

set.seed(120)

Rand_3_3 <- sample.int(365, 1)
Rand_3_4 <- sample.int(365, 1)

因此，我可以为每个人创建“selection frames”：

#Person 1
Rand_1_1 <- sample.int(dim[1], 1)

Rand_1_2 = c( #fill randomly with amount of items specified by Rand_1_1)

Rand_1_3 <- sample.int(365, 1)
Rand_1_4 <- sample.int(365, 1)

#Person 2
Rand_2_1 <- sample.int(dim[1], 1)

Rand_2_2 = c( #fill randomly with amount of items specified by Rand_2_1)

Rand_2_3 <- sample.int(365, 1)
Rand_2_4 <- sample.int(365, 1)


#Person 3
Rand_3_1 <- sample.int(dim[1], 1)

Rand_3_2 = c( #fill randomly with amount of items specified by Rand_3_1)

Rand_3_3 <- sample.int(365, 1)
Rand_3_4 <- sample.int(365, 1)

#Person 4
Rand_4_1 <- sample.int(dim[1], 1)

Rand_4_2 = c( #fill randomly with amount of items specified by Rand_4_1)

Rand_4_3 <- sample.int(365, 1)
Rand_4_4 <- sample.int(365, 1)

但我不知道如何做到这一点才能遵守逻辑约束。最后，我试图制作这样的东西：

#desired results
Person 1 : "apples, tacos" and "4-51"
Person 2: "cookies, nachos, cake, olives", and "56-180"
Person 3: "ice cream", and "200-214"
Person 4: "sushi, popcorn" and "350-365"

有人可以告诉我怎么做吗？

谢谢

Answer 1

这看起来很简单，除非我遗漏了什么，你有一份食物和日子的清单，所以每次你运行通过一个人并且只有 select 来自这些选项：

## initialize the inputs
set.seed(1)
foods <- letters[1:20]
nfoods <- sample(5, 4)
tmp <- list(unpicked = list(food = foods, days = 1:365))

## run it
tmp <- lapply(nfoods, function(x) tmp <<- f(tmp$unpicked$food, x, tmp$unpicked$days))

## summarize it
res <- sapply(seq_along(tmp), function(ii) {
  x <- tmp[[ii]]
  x <- sprintf('person %s: "%s" and "%s"', ii, toString(x$picked$food),
               paste0(x$picked$days, collapse = '-'))
  cat(x, sep = '\n')
  invisible(x)
})
# person 1: "b" and "270-299"
# person 2: "s, a, k, g" and "306-336"
# person 3: "m, t, h" and "42-89"
# person 4: "j, f, q, o, l" and "129-210"


f <- function(food, n, days) {
  # f(1:4, 3, 1:10)
  food1 <- sample(food, n)
  
  days1 <- split(days, cumsum(is.na(days)))
  days1 <- sample(Filter(function(x) length(x) > 2, days1), 1)[[1]]
  days1 <- sort(sample(sort(days1), 2))
  
  days[do.call('seq', as.list(days1))] <- NA
  
  list(
    picked = list(food = food1, days = days1),
    unpicked = list(food = setdiff(food, food1), days = days)
  )
}

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