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.
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.
Examples
# Iterate over two iterables of different sizes
as.list(i_zip(a=1:2, b=letters[1:3]))
#> [[1]]
#> [[1]]$a
#> [1] 1
#>
#> [[1]]$b
#> [1] "a"
#>
#>
#> [[2]]
#> [[2]]$a
#> [1] 2
#>
#> [[2]]$b
#> [1] "b"
#>
#>
it <- i_zip_longest(x=1:3, y=4:6, z=7:9)
nextOr(it, NA) # list(x=1, y=4, z=7)
#> [[1]]
#> [1] 1
#>
#> [[2]]
#> [1] 4
#>
#> [[3]]
#> [1] 7
#>
nextOr(it, NA) # list(x=2, y=5, z=8)
#> [[1]]
#> [1] 2
#>
#> [[2]]
#> [1] 5
#>
#> [[3]]
#> [1] 8
#>
nextOr(it, NA) # list(x=3, y=6, z=9)
#> [[1]]
#> [1] 3
#>
#> [[2]]
#> [1] 6
#>
#> [[3]]
#> [1] 9
#>
it2 <- i_zip_longest(1:3, 4:8)
nextOr(it2, NA) # list(1, 4)
#> [[1]]
#> [1] 1
#>
#> [[2]]
#> [1] 4
#>
nextOr(it2, NA) # list(2, 5)
#> [[1]]
#> [1] 2
#>
#> [[2]]
#> [1] 5
#>
nextOr(it2, NA) # list(3, 6)
#> [[1]]
#> [1] 3
#>
#> [[2]]
#> [1] 6
#>
nextOr(it2, NA) # list(NA, 7)
#> [[1]]
#> [1] NA
#>
#> [[2]]
#> [1] 7
#>
nextOr(it2, NA) # list(NA, 8)
#> [[1]]
#> [1] NA
#>
#> [[2]]
#> [1] 8
#>
it3 <- i_zip_longest(1:2, 4:7, levels(iris$Species), fill="w00t")
nextOr(it3, NA) # list(1, 4, "setosa")
#> [[1]]
#> [1] 1
#>
#> [[2]]
#> [1] 4
#>
#> [[3]]
#> [1] "setosa"
#>
nextOr(it3, NA) # list(2, 5, "versicolor")
#> [[1]]
#> [1] 2
#>
#> [[2]]
#> [1] 5
#>
#> [[3]]
#> [1] "versicolor"
#>
nextOr(it3, NA) # list("w00t", 6, "virginica")
#> [[1]]
#> [1] "w00t"
#>
#> [[2]]
#> [1] 6
#>
#> [[3]]
#> [1] "virginica"
#>
nextOr(it3, NA) # list("w00t", 7, "w00t")
#> [[1]]
#> [1] "w00t"
#>
#> [[2]]
#> [1] 7
#>
#> [[3]]
#> [1] "w00t"
#>