使用数据框中的特定标识符进行有条件突变

Question

我有一个数据集，该数据集采用了类似的方法。

ID <- c(4,5,6,7,3,8,9)
quantity <- c(20,300, 350, 21, 44, 20, 230)
measurementvalue <- c("tin", "kg","kg","tin","tin","tin","kg")
kgs <- c(21,12, 30,23,33,11,24)

DF <- data.frame(ID, quantity, measurementvalue)

我使用条件突变的新列Totalkgs的标准方法是以下代码。

DF <- DF %>%
  mutate(totalkgs = 
           ifelse(quantity == "tin", quantity * 5, 
                  ifelse(quantity =="kg", quantity*1, quantity)))

但是，该数据集在列数量中具有错误的条目，因此我想对这些特定标识符执行划分。乘法和除法的所有最终值都应存储在列totalkgs中。我该怎么做？

让我们假设带有错误数据的ID为3,5,9,7。我想将列数量中的值与10分开。

Answer 1

您可以使用case_when：

ID <- c(4,5,6,7,3,8,9)
quantity <- c(20,300, 350, 21, 44, 20, 230)
measurementvalue <- c("tin", "kg","kg","tin","tin","tin","kg")
kgs <- c(21,12, 30,23,33,11,24)
DF <- data.frame(ID, quantity, measurementvalue)

library(dplyr)
DF %>%
  mutate(quantity2 = ifelse(ID %in% c(3,5,9,7), quantity/10, quantity)) %>%
  mutate(totalkgs = case_when(measurementvalue == "tin" ~ quantity2 * 5,
                              measurementvalue == "kg" ~ quantity2 * 1, 
                              TRUE ~ quantity2)) %>%
  select(-quantity2) #if you want
#>   ID quantity measurementvalue totalkgs
#> 1  4       20              tin    100.0
#> 2  5      300               kg     30.0
#> 3  6      350               kg    350.0
#> 4  7       21              tin     10.5
#> 5  3       44              tin     22.0
#> 6  8       20              tin    100.0
#> 7  9      230               kg     23.0

^{在2022-07-05创建的（v2.0.1）}