CODEWITHSUNDEEP
rdata.table
Konstantinos
Konstantinos

Reputation: 4376

Using `setkey()` inside a function

Take

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')

returns

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

How can I key a data.table from inside a function?

EDIT: For two or more keys...

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"

Upvotes: 3

Views: 557

Answers (1)

akrun
akrun

Reputation: 887501

We can use setkeyv inside the function

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"

Upvotes: 4

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