OrderedMap

Chinese version: 中文

Summary

OrderedMap is a map which preserving the key order as they are added to the map.

Feature

• Simple
• Fast(Use json.Decoder for unmarshaling)
• Powerful API
• Well documented
• Marshaling & UnMarshaling support.

Usage

package main

import (
    "fmt"
    "encoding/json"
    "github.com/haifenghuang/orderedmap"
)

func main() {
    om := orderedmap.New()
    om.Set("Name", "HuangHaiFeng")
    om.Set("Sex", "Male")
    om.Set("Hobby", "Programming")
    om.Set("Country", "China")

    hobby, _ := om.Get("Hobby")
    fmt.Printf("Hobby = %s\n", hobby)

    sex, _ := om.GetAt(1)
    fmt.Printf("sex = %v\n", sex)

    om.SetAt(2, "Married", true)
    married, _ := om.GetAt(2)
    fmt.Printf("married = %t\n", married)

    fmt.Printf("=============================\n")
    fmt.Printf("keys = %v\n", om.Keys())
    fmt.Printf("values = %v\n", om.Values())
    fmt.Printf("mapLen = %d\n", om.Len())

    fmt.Printf("=============================\n")
    om.DeleteAt(2)
    fmt.Printf("OrderedMap = %s\n", om)

    fmt.Printf("=============================\n")
    has := om.Exists("Married")
    fmt.Printf("Married? - %t\n", has)
    has = om.Exists("Country")
    fmt.Printf("Country? - %t\n", has)

    fmt.Printf("=============================\n")
    idx := om.Index("Hobby")
    fmt.Printf("Hobby key's index = %d\n", idx)

    fmt.Printf("=============================\n")
    b, _ := json.MarshalIndent(om, "", "    ")
    fmt.Printf("Marshal result = %s\n", string(b))

    fmt.Printf("=============================\n")
    jsonStream := `{
    "Name": "HuangHaiFeng",
    "Sex": "Male",
    "Hobby": "Programming",
    "Country": "China"
}`
    om2 := orderedmap.New()
    _ = json.Unmarshal([]byte(jsonStream), om2)
    fmt.Printf("om2 = %v\n", om2)

    om2.Sort()
    fmt.Printf("==============================\n")
    fmt.Printf("om2 = %v\n", om2)

    om3 := om2.Reverse()
    fmt.Printf("==============================\n")
    fmt.Printf("om3 = %v\n", om3)

    om4 := om3.Filter(func(key string,value interface{}) bool {
        return key == "China" || key == "Male"
    })
    fmt.Printf("==============================\n")
    fmt.Printf("om4 = %v\n", om4)
}

Limitation

• OrderedMap only takes strings for the key.
• OrderedMap is not thread-safe for concurrent use.(It is simple enough to add one using sync.RWMutex)

API

Function	Description
New()	New create a new OrderedMap.
Get(key string)	Get returns the value of the map based on its key.
GetAt(pos int)	GetAt returns the value based on the provided pos.
Set(key string, value interface{})	Set sets the key/value of the map based on key and value.
SetAt(index int, key string, val interface{})	SetAt sets the given key to the given value at the specified index.
Delete(key string)	Delete remove an item from the map by the supplied key.
DeleteAt(offset int)	DeleteAt delete the key/value pair from the map by the supplied offset.
Keys()	Keys return the keys of the map in the order they were added.
Values()	Values returns a slice of the values in the order they were added.
Exists(key string)	Exists test whether the key exists or not.
Index(key string)	Index returns the offset of the key in the ordered map.
Len()	Len returns the length of the map.
String()	String returns the JSON serialized string representation.
Reverse()	Reverse reverse key & value of a map. The value must be a string.
Sort()	Sort the given OrderedMap.
Filter(f func(key string, value interface{}) bool)	Filter an OrderedMap if the provided function return true.
MarshalJSON() ([]byte, error)	MarshalJSON implements the json.Marshaller interface.
UnmarshalJSON(b []byte) error	UnmarshalJSON implements the json.Unmarshaller interface.

Alternatives

• cevaris/ordered_map Not support marshaling/unmarshaling.

• iancoleman/orderedmap Unmarshaling is self-written, not using json.Decoder.

License

MIT

Remarks

If you like this repo，please star & fork. Thanks!