odbtest/test/arrow/array.go

package main

import (
	"fmt"

	"github.com/apache/arrow/go/arrow"
	"github.com/apache/arrow/go/arrow/array"
	"github.com/apache/arrow/go/arrow/memory"
)

func main() {
	pool := memory.NewGoAllocator()

	lb := array.NewListBuilder(pool, arrow.PrimitiveTypes.Int64)
	defer lb.Release()

	vb := lb.ValueBuilder().(*array.Int64Builder)
	defer vb.Release()

	vb.Reserve(10)

	lb.Append(true)
	vb.Append(0)
	vb.Append(1)
	vb.Append(2)

	lb.AppendNull()

	lb.Append(true)
	vb.Append(3)

	lb.Append(true)
	vb.Append(4)
	vb.Append(5)

	lb.Append(true)
	vb.Append(6)
	vb.Append(7)
	vb.Append(8)

	lb.AppendNull()

	lb.Append(true)
	vb.Append(9)

	arr := lb.NewArray().(*array.List)
	defer arr.Release()

	fmt.Printf("NullN()   = %d\n", arr.NullN())
	fmt.Printf("Len()     = %d\n", arr.Len())
	fmt.Printf("Offsets() = %v\n", arr.Offsets())

	offsets := arr.Offsets()[1:]

	varr := arr.ListValues().(*array.Int64)

	pos := 0
	for i := 0; i < arr.Len(); i++ {
		if !arr.IsValid(i) {
			fmt.Printf("List[%d]   = (null)\n", i)
			continue
		}
		fmt.Printf("List[%d]   = [", i)
		for j := pos; j < int(offsets[i]); j++ {
			if j != pos {
				fmt.Printf(", ")
			}
			fmt.Printf("%v", varr.Value(j))
		}
		pos = int(offsets[i])
		fmt.Printf("]\n")
	}
	fmt.Printf("List      = %v\n", arr)

}