datatable

Installation

go get github.com/datasweet/datatable

Features

Creating a DataTable

package main
import (
	"fmt"
	"github.com/datasweet/datatable"
)
func main() {
	dt := datatable.New("test")
	dt.AddColumn("champ", datatable.String, datatable.Values("Malzahar", "Xerath", "Teemo"))
	dt.AddColumn("champion", datatable.String, datatable.Expr("upper(`champ`)"))
	dt.AddColumn("win", datatable.Int, datatable.Values(10, 20, 666))
	dt.AddColumn("loose", datatable.Int, datatable.Values(6, 5, 666))
	dt.AddColumn("winRate", datatable.Float64, datatable.Expr("`win` * 100 / (`win` + `loose`)"))
	dt.AddColumn("winRate %", datatable.String, datatable.Expr(" `winRate` ~ \" %\""))
	dt.AddColumn("sum", datatable.Float64, datatable.Expr("sum(`win`)"))
	fmt.Println(dt)
}
/*
CHAMP <NULLSTRING> CHAMPION <NULLSTRING> WIN <NULLINT> LOOSE <NULLINT> WINRATE <NULLFLOAT64> WINRATE % <NULLSTRING> SUM <NULLFLOAT64> 
Malzahar MALZAHAR 10 6 62.5 62.5 % 696 
Xerath XERATH 20 5 80 80 % 696 
Teemo TEEMO 666 666 50 50 % 696 
*/

Reading a CSV and aggregate

package main
import (
	"fmt"
	"log"
	"os"
	"time"
	"github.com/datasweet/datatable"
	"github.com/datasweet/datatable/import/csv"
)
func main() {
	dt, err := csv.Import("csv", "phone_data.csv",
		csv.HasHeader(true),
		csv.AcceptDate("02/01/06 15:04"),
		csv.AcceptDate("2006-01"),
	)
	if err != nil {
		log.Fatalf("reading csv: %v", err)
	}
	dt.Print(os.Stdout, datatable.PrintMaxRows(24))
	dt2, err := dt.Aggregate(datatable.AggregateBy{Type: datatable.Count, Field: "index"})
	if err != nil {
		log.Fatalf("aggregate COUNT('index'): %v", err)
	}
	fmt.Println(dt2)
	groups, err := dt.GroupBy(datatable.GroupBy{
		Name: "year",
		Type: datatable.Int,
		Keyer: func(row datatable.Row) (interface{}, bool) {
			if d, ok := row["date"]; ok {
				if tm, ok := d.(time.Time); ok {
					return tm.Year(), true
				}
			}
			return nil, false
		},
	})
	if err != nil {
		log.Fatalf("GROUP BY 'year': %v", err)
	}
	dt3, err := groups.Aggregate(
		datatable.AggregateBy{Type: datatable.Sum, Field: "duration"},
		datatable.AggregateBy{Type: datatable.CountDistinct, Field: "network"},
	)
	if err != nil {
		log.Fatalf("Aggregate SUM('duration'), COUNT_DISTINCT('network') GROUP BY 'year': %v", err)
	}
	fmt.Println(dt3)
}

Creating a custom serie

// IntN is an alis to create the custom Serie to manage IntN
func IntN(v ...interface{}) Serie {
	s, _ := New(NullInt{}, asNullInt, compareNullInt)
	if len(v) > 0 {
		s.Append(v...)
	}
	return s
}
type NullInt struct {
	Int int
	Valid bool
}
// Interface() to render the current struct as a value.
// If not provided, the serie.All() or serie.Get() wills returns the embedded value
// IE: NullInt{}
func (i NullInt) Interface() interface{} {
	if i.Valid {
		return i.Int
	}
	return nil
}
// asNullInt is our caster function
func asNullInt(i interface{}) NullInt {
	var ni NullInt
	if i == nil {
		return ni
	}
	if v, ok := i.(NullInt); ok {
		return v
	}
	if v, err := cast.ToIntE(i); err == nil {
		ni.Int = v
		ni.Valid = true
	}
	return ni
}
// compareNullInt is our comparator function
// used to sort
func compareNullInt(a, b NullInt) int {
	if !b.Valid {
		if !a.Valid {
			return Eq
		}
		return Gt
	}
	if !a.Valid {
		return Lt
 }
 if a.Int == b.Int {
		return Eq
	}
	if a.Int < b.Int {
		return Lt
	}
	return Gt
}

Who are we ?

Questions ? problems ? suggestions ?

Contributors

License

This software is licensed under the Apache License, version 2 ("ALv2"), quoted below.
Copyright 2017-2020 Datasweet <http://www.datasweet.fr>
Licensed under the Apache License, Version 2.0 (the "License"); you may not
use this file except in compliance with the License. You may obtain a copy of
the License at
 http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
License for the specific language governing permissions and limitations under
the License.