Returns true if the float64 slice is nil or has zero elements.
| Field | Type | Description |
|---|---|---|
Value | *[]float64 | Slice to test |
| Field | Type | Description |
|---|---|---|
Match | bool | True if nil or zero-length |
Guards a downstream aggregation step by detecting when a scoring step returned no results.
package main
import (
"context"
"encoding/json"
"log"
"os"
"time"
"github.com/akennis/sparsi-go/library"
_ "github.com/akennis/dagor/operator/builtin"
"github.com/panjf2000/ants/v2"
"github.com/akennis/dagor"
"github.com/akennis/dagor/graph"
)
func main() {
scores := []float64{}
library.RegisterConst("scores", scores)
g, err := graph.NewBuilder("empty_slice_float_demo").
Vertex("src").Op("scores").Output("Result", "scores_wire").
Vertex("check").Op("IfEmptySliceFloat64Op").
Input("Value", "scores_wire").
Output("Match", "is_empty").
Build()
if err != nil {
log.Fatalf("build: %v", err)
}
pool, err := ants.NewPool(4)
if err != nil {
log.Fatalf("pool: %v", err)
}
defer pool.Release()
eng, err := dagor.NewEngine(g, pool)
if err != nil {
log.Fatalf("engine: %v", err)
}
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
defer cancel()
if err := eng.Run(ctx); err != nil {
log.Fatalf("run: %v", err)
}
out := map[string]any{"scores": scores}
if raw, ok := eng.GetOutput("is_empty"); ok {
out["is_empty"] = *raw.(*bool)
}
enc := json.NewEncoder(os.Stdout)
enc.SetIndent("", " ")
enc.Encode(out)
}