r - 在函数内部使用 `setkey()`

Question

拿

DT <- CJ(1:2, 2:3)

key.the.DT <- function(data.table, primary.key)
                       setkey(data.table, primary.key) 

key.the.DT(data.table = DT, primary.key = 'V1')

返回

Error in setkeyv(x, cols, verbose = verbose, physical = physical) : 
  some columns are not in the data.table: primary.key

如何从函数内部键入 data.table？

编辑:对于两个或更多键...

DT <- CJ(1:2, 2:3, 4:5)

key.the.DT <- function(data.table, the.keys)
                       setkeyv(data.table, the.keys) 
setkey(DT, 'V3')
key(DT)
# [1] "V3"
key.the.DT(data.table = DT, the.keys = c('V1', 'V2'))
key(DT)
# [1] "V1" "V2"

Answer 1

我们可以在函数内部使用setkeyv

key.the.DT <- function(data.table, primary.key)
                    setkeyv(data.table, primary.key) 
key.the.DT(data.table = DT, primary.key = 'V1')
key(DT)
#[1] "V1"