R : How to get a single element in data.table

Question

I want to get the first element from data.table

library(data.table)
dt <- data.table(data.frame(prices=c(1.1,2.4,5.3),
                            dates = c(2011-01-04,2011-01-05,2011-01-03)))
dt
     date       value
 1: 2011-01-04   1.1
 2: 2011-01-05   2.4
 3: 2011-01-03   5.3
> dt[1,1]
[1] 1
> dt[1]
     date       value
 1: 2011-01-04   1.1
> dt[1][1]
     date       value
 1: 2011-01-04   1.1

I need to get the first date. I'm not sure what i'm missing here :(

Thanks a lot. I was bit confused with the output.

dt[1, date]
[1] 2011-01-04
Levels: 2011-01-03 2011-01-04 2011-01-05 (any idea what levels mean?)

This also works st$date[1]. Implementation is same as data frame.

Answer 1

Perhaps:

dt[1, date]

One of the joys of using data.table's is that the expressions in the 'j' position get evaluated in the context of the existing named columns. No need to use with().