i_zip {iterors}

Combine several iterables in parallel.

Description

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

Usage

i_zip(...)

i_zip_longest(..., fill = NA)

Arguments

...

multiple arguments to iterate through in parallel

fill

the value used to replace missing values when the iterables in ... are of uneven length

Details

For ⁠[i_zip]⁠, the output will finish when any of the underlying iterables finish.

Originally from the itertools package.

Originally from package itertools2.

Value

iterator that iterates through each argument in sequence

Examples

# Iterate over two iterables of different sizes
as.list(i_zip(a=1:2, b=letters[1:3]))

it <- i_zip_longest(x=1:3, y=4:6, z=7:9)
nextOr(it, NA) # list(x=1, y=4, z=7)
nextOr(it, NA) # list(x=2, y=5, z=8)
nextOr(it, NA) # list(x=3, y=6, z=9)

it2 <- i_zip_longest(1:3, 4:8)
nextOr(it2, NA) # list(1, 4)
nextOr(it2, NA) # list(2, 5)
nextOr(it2, NA) # list(3, 6)
nextOr(it2, NA) # list(NA, 7)
nextOr(it2, NA) # list(NA, 8)

it3 <- i_zip_longest(1:2, 4:7, levels(iris$Species), fill="w00t")
nextOr(it3, NA) # list(1, 4, "setosa")
nextOr(it3, NA) # list(2, 5, "versicolor")
nextOr(it3, NA) # list("w00t", 6, "virginica")
nextOr(it3, NA) # list("w00t", 7, "w00t")