Filtering

Filtering operates on Ranges. It scans the range and skips any documents that the provided filter function returns false for.

Definition

func (r *Range) Filter(filter func(doc Document) (bool, error)) *Range

Example use

package main

import (
	"github.com/1lann/cete"
	"fmt"
)

type Person struct {
	Name string
	Age int
}

func main() {
	db, _ := cete.Open("./cete_data")

	defer db.Close()

	db.NewTable("people")
	db.Table("people").Set("ash", Person{
		Name: "Ash Ketchum",
		Age: 10,
	})
	db.Table("people").Set("brock", Person{
		Name: "Brock",
		Age: 15,
	})

	// Find who is older than 13
	r := db.Table("people").All().Filter(func(doc cete.Document) (bool, error) {
		return doc.QueryInt("Age") > 13, nil
	})

	var person Person
	r.Next(&person)
	fmt.Printf("%+v\n", person) // Should print Brock's information
}

// Find whose name starts with Ash
r := db.Table("people").All().Filter(func(doc cete.Document) (bool, error) {
	return strings.HasPrefix(doc.QueryString("Name"), "Ash"), nil
})

// You can reference other tables in your filter and specify the number
// of workers to use when filtering to speed up the filter.
r := db.Table("people").All().Filter(func(doc cete.Document) (bool, error) {
	var poke Pokemon
	_, _, err := db.Table("pokemon").Index("trainer").One(doc.QueryString("Name"), &poke)
	return poke.Name == "Pikachu", err
}, 20) // <-- Note that the number of workers is specified here