Break a list into fixed-size pieces
A bulk API takes at most a hundred records per call, so a long list has to be handed over in pieces.
- Every piece is the given size except possibly the last, which takes what is left.
- A size of zero or less gives an empty result.
- An empty input gives an empty result, not a list holding one empty piece.
chunkList(values: list<int>, perChunk: int) → list<list<int>>
Go needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
func chunkList(values []int, perChunk int) [][]int {
}Worked examples
| Call | Result |
|---|---|
chunkList([]int{1, 2, 3, 4, 5}, 2) | [][]int{[]int{1, 2}, []int{3, 4}, []int{5}} |
chunkList([]int{1, 2, 3, 4}, 2) | [][]int{[]int{1, 2}, []int{3, 4}} |
chunkList([]int{1}, 5) | [][]int{[]int{1}} |
chunkList([]int{}, 2) | [][]int{} |
Hint
Step the index forward by the chunk size and slice, rather than pushing one item at a time.
Reference solution in Go
func chunkList(values []int, perChunk int) [][]int {
result := [][]int{}
if perChunk <= 0 {
return result
}
for i := 0; i < len(values); i += perChunk {
j := i + perChunk
if j > len(values) {
j = len(values)
}
result = append(result, append([]int{}, values[i:j]...))
}
return result
}