Select column of data.table and return vector

Question

Is it possible to select a column of a data.table and get back a vector? In base R, the argument drop=TRUE would do the trick. For example,

library(         


        

Answer 1

With data.frame, the default is drop = TRUE and in data.table, it is the opposite while it is done internally. According to ?data.table

drop - Never used by data.table. Do not use. It needs to be here because data.table inherits from data.frame.

In order to get the same behavior, we can use [[ to extract the column by passing a string

identical(dat[["Species"]], iris[, "Species"])
#[1] TRUE

Or

dat$Species

By using [[ or $, it extracts as a vector while also bypass the data.table overhead

Answer 2

See data.table FAQ #1.1. This comes as a feature since 2006.