Returns the first/last item of a vector or list, or the first/last row of a data.frame
or data.table. The main difference to head/tail is that the default for `n`

is 1
rather than 6.

first(x, n=1L, ...)
last(x, n=1L, ...)

## Arguments

x |
A vector, list, data.frame or data.table. Otherwise the S3 method
of `xts::first` is deployed. |

n |
A numeric vector length 1. How many items to select. |

... |
Not applicable for `data.table` first/last. Any arguments here
are passed through to `xts` 's first/last. |

## Value

If no other arguments are supplied it depends on the type of `x`

. The first/last item
of a vector or list. The first/last row of a `data.frame`

or `data.table`

.
For other types, or if any argument is supplied in addition to `x`

(such as `n`

, or
`keep`

in `xts`

) regardless of `x`

's type, then `xts::first`

/
`xts::last`

is called if `xts`

has been loaded, otherwise `utils::head`

/`utils::tail`

.

## See also

## Examples

first(1:5) # [1] 1

#> [1] 1

x = data.table(x=1:5, y=6:10)
first(x) # same as head(x, 1)

#> x y
#> 1: 1 6

last(1:5) # [1] 5

#> [1] 5

x = data.table(x=1:5, y=6:10)
last(x) # same as tail(x, 1)

#> x y
#> 1: 5 10