我在哪里做错了[关闭]

Question

我正在尝试制作一个 r 代码来计算虚构产品的price。它有无限数量，但在您购买25 之后价格会发生变化。它永远保持不变。价格为2,5,8,12,15,20。这是我的代码：

n<-c(0:9999)
countchange<-seq(25,150, by=25)
price<-c(2,5,8,12,15,20)

for (n in 0:9999) {
   if(n<countchange) {price=price[1]}
    else{price}
  }

pricechange<-function(n){
  coinssum<-n*price
  return(coinssum)  
}

pricechange

Answer 1

由于我有点猜测您在这里尝试实现的目标，这里是我猜测的解决方案：

library(tidyverse)

whatCaniAfford <- function(coins){
  price <- tibble(price = c(2,5,8,12,15,20)) %>%
    mutate(
      treshold = cumsum(price*25),
      budget = coins-treshold)
  
  price %>%
    mutate(afford = case_when(
      coins <= 50 & price == 2 ~ floor(coins/2),
      coins <= 50 & price > 2 ~ 0,
      budget > 0 & price < 20 ~ 25,
      budget > 0 & price == 20 ~ floor(lag(budget)/20),
      budget < 0  ~ floor(lag(budget)/price)
    )) %>%
    filter(afford > 0) %>%
    select(price, afford)
  
}

whatCaniAfford(coins = 1000)

# A tibble: 5 × 2
price afford
<dbl>  <dbl>
1     2     25
2     5     25
3     8     25
4    12     25
5    15     21