nth: Returns the nth item of an iterator

In itertools2: itertools2: Functions creating iterators for efficient looping

Description

Returns the nth item of an iterator after advancing the iterator n steps ahead. If the iterator is entirely consumed, the default value is returned instead. That is, if either n > length(iterator) or n is 0, then the iterator is consumed.

Usage

nth(iterator, n, default = NA)

Arguments

iterator	an iterator object
n	The location of the desired element to return
default	The value to return if iterable is consumed, default is NA

Value

The nth element of the iterable or the default value

Examples

it <- iterators::iter(1:10)
# Returns 5
nth(it, 5)

it2 <- iterators::iter(letters)
# Returns 'e'
nth(it2, 5)

it3 <- iterators::iter(letters)
# Returns default value of NA
nth(it3, 42)

it4 <- iterators::iter(letters)
# Returns default value of "foo"
nth(it4, 42, default="foo")

Example output

[1] 5
[1] "e"
[1] NA
[1] "foo"

itertools2 documentation built on May 2, 2019, 3:37 p.m.