Subset first or last rows — head.dtplyr

These are methods for the base generics head() and tail(). They are not translated.

Usage

# S3 method for dtplyr_step
head(x, n = 6L, ...)

# S3 method for dtplyr_step
tail(x, n = 6L, ...)

Arguments

x: A lazy_dt()
n: Number of rows to select. Can use a negative number to instead drop rows from the other end.
...: Passed on to head()/tail().

Examples

library(dplyr, warn.conflicts = FALSE)
dt <- lazy_dt(data.frame(x = 1:10))

# first three rows
head(dt, 3)
#> Source: local data table [3 x 1]
#> Call:   head(`_DT17`, n = 3)
#> 
#>       x
#>   <int>
#> 1     1
#> 2     2
#> 3     3
#> 
#> # Use as.data.table()/as.data.frame()/as_tibble() to access results
# last three rows
tail(dt, 3)
#> Source: local data table [3 x 1]
#> Call:   tail(`_DT17`, n = 3)
#> 
#>       x
#>   <int>
#> 1     8
#> 2     9
#> 3    10
#> 
#> # Use as.data.table()/as.data.frame()/as_tibble() to access results

# drop first three rows
tail(dt, -3)
#> Source: local data table [7 x 1]
#> Call:   tail(`_DT17`, n = -3)
#> 
#>       x
#>   <int>
#> 1     4
#> 2     5
#> 3     6
#> 4     7
#> 5     8
#> 6     9
#> # … with 1 more row
#> 
#> # Use as.data.table()/as.data.frame()/as_tibble() to access results