izip {itertools2}

Iterator that iterates through several iterables concurrently.

Description

The resulting iterator aggregates elements from each of the iterables into a list from each iteration. Used for lock-step iteration over several iterables at a time.

Usage

izip(...)

Arguments

...

multiple arguments to iterate through in sequence

Value

iterator that iterates through each argument in sequence

Examples

it <- izip(x=1:3, y=4:6, z=7:9)
iterators::nextElem(it) # list(x=1, y=4, z=7)
iterators::nextElem(it) # list(x=2, y=5, z=8)
iterators::nextElem(it) # list(x=3, y=6, z=9)

# Sums the zip'd elements. 1 + 4 + 7, and so on.
it2 <- izip(1:3, 4:6, 7:9)
sum_zip <- sapply(it2, function(x) sum(unlist(x)))
sum_zip == c(12, 15, 18)

it3 <- izip(a=1:3, b=4:42, class=levels(iris$Species))
iterators::nextElem(it3) # list(a=1, b=4, class="setosa")
iterators::nextElem(it3) # list(a=2, b=5, class="versicolor")
iterators::nextElem(it3) # list(a=3, b=6, class="virginica")