get(as.character(FUN), mode = “function”, envir = envir) 中的错误：

Question

我正在尝试将此函数应用于数据框以创建新功能，但我不断收到此错误：

get(as.character(FUN), mode = "function", envir = envir) 中的错误：找不到模式 'function' 的对象 'INSTALLMENT'

我也试过apply(df, 2, purchase)但后来我得到这个错误：

错误：$ 运算符对原子向量无效

代码是：

purchase = function(DataFrame){

  if((DataFrame$ONEOFF_PURCHASES == 0) && (DataFrame$INSTALLMENTS_PURCHASES == 0))
    return('NONE')

  if((DataFrame$ONEOFF_PURCHASES > 0) && (DataFrame$INSTALLMENTS_PURCHASES > 0))
    return('BOTH_ONEOFF_INSTALLMENT')

  if((DataFrame$ONEOFF_PURCHASES > 0) && (DataFrame$INSTALLMENTS_PURCHASES == 0))
    return('ONE_OFF')

  if((DataFrame$ONEOFF_PURCHASES == 0) && (DataFrame$INSTALLMENTS_PURCHASES > 0))
    return('INSTALLMENT')
}

df$PURCHASE_TYPE = apply(df, 2, purchase(df))

Answer 1

它看起来像一个ifelse()案例。 if() ... else ...只能处理单个布尔值。 为了使您的函数工作，您需要通过mapply()或Vectorize() 。

示例数据

set.seed(1)
df <- data.frame(ONEOFF_PURCHASES = sample(0:1, 5, T), INSTALLMENTS_PURCHASES = sample(0:1, 5, T))

#   ONEOFF_PURCHASES INSTALLMENTS_PURCHASES
# 1                0                      0
# 2                1                      0
# 3                0                      0
# 4                0                      1
# 5                1                      1

功能

purchase <- function(x, y){
  if((x == 0) && (y == 0))
    return('NONE')
  else if((x > 0) && (y > 0))
    return('BOTH_ONEOFF_INSTALLMENT')
  else if((x > 0) && (y == 0))
    return('ONE_OFF')
  else if((x == 0) && (y > 0))
    return('INSTALLMENT')
  else
    return('OTHERS')
}

矢量化

mapply(purchase, df$ONEOFF_PURCHASES, df$INSTALLMENTS_PURCHASES)
# [1] "NONE"  "ONE_OFF"  "NONE"  "INSTALLMENT"  "BOTH_ONEOFF_INSTALLMENT"

Vectorize(purchase)(df$ONEOFF_PURCHASES, df$INSTALLMENTS_PURCHASES)
# [1] "NONE"  "ONE_OFF"  "NONE"  "INSTALLMENT"  "BOTH_ONEOFF_INSTALLMENT"

---

实际上，我们在这个问题中没有使用上面的方法。 我们将使用ifelse()或dplyr::case_when() 。

library(dplyr)

df %>%
  mutate(PURCHASE_TYPE = case_when(
    (ONEOFF_PURCHASES == 0) & (INSTALLMENTS_PURCHASES == 0) ~ 'NONE',
    (ONEOFF_PURCHASES > 0) & (INSTALLMENTS_PURCHASES > 0) ~ 'BOTH_ONEOFF_INSTALLMENT',
    (ONEOFF_PURCHASES > 0) & (INSTALLMENTS_PURCHASES == 0) ~ 'ONE_OFF',
    (ONEOFF_PURCHASES == 0) & (INSTALLMENTS_PURCHASES > 0) ~ 'INSTALLMENT',
    TRUE ~ 'OTHERS'
  ))

#   ONEOFF_PURCHASES INSTALLMENTS_PURCHASES           PURCHASE_TYPE
# 1                0                      0                    NONE
# 2                1                      0                 ONE_OFF
# 3                0                      0                    NONE
# 4                0                      1             INSTALLMENT
# 5                1                      1 BOTH_ONEOFF_INSTALLMENT