r-create函数，用于计算数据集中已筛选行的计数

我正在尝试创建一个助手函数，该函数将根据参数计算data.frame中有多少行

getTotalParkeds <- function(place, weekday, entry_hour){
  data <- PARKEDS[
                  PARKEDS$place      == place,
                  PARKEDS$weekday    == weekday,
                  PARKEDS$entry_hour == entry_hour
                  ]
  return(nrow(data))
}

所以它返回了这个错误：

Warning: Error in : Length of logical index vector must be 1 or 11 (the number of columns), not 10000

---

我对R完全是新手，所以我不知道发生了什么事。

这里是你需要对你的方法进行修正的地方-

getTotalParkeds <- function(place, weekday, entry_hour){
  data <- PARKEDS[
                  PARKEDS$place      == place &
                  PARKEDS$weekday    == weekday &
                  PARKEDS$entry_hour == entry_hour,
                  ]
  return(nrow(data))
}

---

getTotalMarkeds允许不同的
parked
数据，比如下个月的数据：

getTotalParkeds <- function(input, place, weekday, entry_hour){

  row.count <- nrow(subset(input, place == place & 
                                  weekday == weekday & 
                                  entry_hour == entry_hour))
  return(row.count)
}

getTotalMarkeds
getTotalParkeds <- function(input, place, weekday, entry_hour){

  row.count <- nrow(subset(input, place == place & 
                                  weekday == weekday & 
                                  entry_hour == entry_hour))
  return(row.count)
}