Map - Usage
- Concurrent Safety
- Usage Example

Map - Usage

Concurrent Safety

gmap supports a concurrency-safe option switch, which is not concurrency-safe by default. Developers can choose to enable the concurrency-safe feature of gmap (passing the initialization switch parameter safe value as true, it must be set during initialization and cannot be dynamically set at runtime). For example:

m := gmap.New(true)

Not only the gmap module, but other concurrent-safe data structures of the goframe framework also support the concurrent safety feature switch.

Usage Example

Basic Usage

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/gmap"
)

func main() {
    // Create a default gmap object,
    // By default, this gmap object does not support concurrency safety features,
    // A true parameter can be given during initialization to enable concurrent safety features.
    m := gmap.New()

    // Set key-value pairs
    for i := 0; i < 10; i++ {
        m.Set(i, i)
    }
    // Query size
    fmt.Println(m.Size())
    // Batch set key-value pairs (different data type objects have different parameters)
    m.Sets(map[interface{}]interface{}{
        10: 10,
        11: 11,
    })
    fmt.Println(m.Size())

    // Check if it exists
    fmt.Println(m.Contains(1))

    // Query value
    fmt.Println(m.Get(1))

    // Delete item
    m.Remove(9)
    fmt.Println(m.Size())

    // Batch delete
    m.Removes([]interface{}{10, 11})
    fmt.Println(m.Size())

    // Current key list (random order)
    fmt.Println(m.Keys())
    // Current value list (random order)
    fmt.Println(m.Values())

    // Query key name, and write the given default value when the key value does not exist
    fmt.Println(m.GetOrSet(100, 100))

    // Delete key-value pair, returning the corresponding key value
    fmt.Println(m.Remove(100))

    // Traverse map
    m.Iterator(func(k interface{}, v interface{}) bool {
        fmt.Printf("%v:%v ", k, v)
        return true
    })

    // Custom write lock operation
    m.LockFunc(func(m map[interface{}]interface{}) {
        m[99] = 99
    })

    // Custom read lock operation
    m.RLockFunc(func(m map[interface{}]interface{}) {
        fmt.Println(m[99])
    })

    // Clear map
    m.Clear()

    // Check if the map is empty
    fmt.Println(m.IsEmpty())
}

After execution, the output is:

12
true
1
11
9
[0 1 2 4 6 7 3 5 8]
[3 5 8 0 1 2 4 6 7]
100
100
3:3 5:5 8:8 7:7 0:0 1:1 2:2 4:4 6:6 99
true

Ordered Traversal

Let‘s take a look at examples of ordered traversal for three different types of map.

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/frame/g"
    "github.com/gogf/gf/v2/container/gmap"
    "github.com/gogf/gf/v2/util/gutil"
)

func main() {
    array   := g.Slice{2, 3, 1, 5, 4, 6, 8, 7, 9}
    hashMap := gmap.New(true)
    listMap := gmap.NewListMap(true)
    treeMap := gmap.NewTreeMap(gutil.ComparatorInt, true)
    for _, v := range array {
        hashMap.Set(v, v)
    }
    for _, v := range array {
        listMap.Set(v, v)
    }
    for _, v := range array {
        treeMap.Set(v, v)
    }
    fmt.Println("HashMap   Keys:", hashMap.Keys())
    fmt.Println("HashMap Values:", hashMap.Values())
    fmt.Println("ListMap   Keys:", listMap.Keys())
    fmt.Println("ListMap Values:", listMap.Values())
    fmt.Println("TreeMap   Keys:", treeMap.Keys())
    fmt.Println("TreeMap Values:", treeMap.Values())
}

After execution, the output is:

HashMap   Keys: [4 6 8 7 9 2 3 1 5]
HashMap Values: [6 8 4 3 1 5 7 9 2]
ListMap   Keys: [2 3 1 5 4 6 8 7 9]
ListMap Values: [2 3 1 5 4 6 8 7 9]
TreeMap   Keys: [1 2 3 4 5 6 7 8 9]
TreeMap Values: [1 2 3 4 5 6 7 8 9]

`FilterEmpty/FilterNil` Empty Value Filtering

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/gmap"
    "github.com/gogf/gf/v2/frame/g"
)

func main() {
    m1 := gmap.NewFrom(g.MapAnyAny{
        "k1": "",
        "k2": nil,
        "k3": 0,
        "k4": 1,
    })
    m2 := gmap.NewFrom(g.MapAnyAny{
        "k1": "",
        "k2": nil,
        "k3": 0,
        "k4": 1,
    })
    m1.FilterEmpty()
    m2.FilterNil()
    fmt.Println(m1.Map())
    fmt.Println(m2.Map())

    // Output:
    // map[k4:1]
    // map[k1: k3:0 k4:1]
}

`Flip` Key-Value Pair Reversal

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/gmap"
    "github.com/gogf/gf/v2/frame/g"
)

func main() {
    var m gmap.Map
    m.Sets(g.MapAnyAny{
        "k1": "v1",
        "k2": "v2",
    })
    m.Flip()
    fmt.Println(m.Map())

    // May Output:
    // map[v1:k1 v2:k2]
}

`Keys/Values` Key/Value Lists

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/gmap"
    "github.com/gogf/gf/v2/frame/g"
)

func main() {
    var m gmap.Map
    m.Sets(g.MapAnyAny{
        "k1": "v1",
        "k2": "v2",
        "k3": "v3",
        "k4": "v4",
    })
    fmt.Println(m.Keys())
    fmt.Println(m.Values())

    // May Output:
    // [k1 k2 k3 k4]
    // [v2 v3 v4 v1]
}

`Pop/Pops` Random Pop

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/gmap"
    "github.com/gogf/gf/v2/frame/g"
)

func main() {
    var m gmap.Map
    m.Sets(g.MapAnyAny{
        "k1": "v1",
        "k2": "v2",
        "k3": "v3",
        "k4": "v4",
    })
    fmt.Println(m.Pop())
    fmt.Println(m.Pops(2))
    fmt.Println(m.Size())

    // May Output:
    // k1 v1
    // map[k2:v2 k4:v4]
    // 1
}

`SetIfNotExist*` Conditional Setting

Conditional setting means writing to the map only when the specified key does not exist, and the method returns true; otherwise, it ignores the write and the method returns false. Relevant methods include:

SetIfNotExist
SetIfNotExistFunc
SetIfNotExistFuncLock

For detailed descriptions, please refer to the interface documentation or source code comments.

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/gmap"
)

func main() {
    var m gmap.Map
    fmt.Println(m.SetIfNotExist("k1", "v1"))
    fmt.Println(m.SetIfNotExist("k1", "v1"))
    fmt.Println(m.Map())

    // Output:
    // true
    // false
    // map[k1:v1]
}

`Merge` Dictionary Merge

package main

import (
    "fmt"
    "github.com/gogf/gf/v2/container/gmap"
)

func main() {
    var m1, m2 gmap.Map
    m1.Set("key1", "val1")
    m2.Set("key2", "val2")
    m1.Merge(&m2)
    fmt.Println(m1.Map())

    // May Output:
    // map[key1:val1 key2:val2]
}

`JSON` Serialization/Deserialization

All container types under the gmap module implement the standard library json data format serialization/deserialization interfaces.

Marshal

package main

import (
    "encoding/json"
    "fmt"
    "github.com/gogf/gf/v2/frame/g"

    "github.com/gogf/gf/v2/container/gmap"
)

func main() {
    m := gmap.New()
    m.Sets(g.MapAnyAny{
        "name":  "john",
        "score": 100,
    })
    b, _ := json.Marshal(m)
    fmt.Println(string(b))
}

After execution, the output is:

{"name":"john","score":100}

Unmarshal

package main

import (
    "encoding/json"
    "fmt"
    "github.com/gogf/gf/v2/container/gmap"
)

func main() {
    m := gmap.Map{}
    s := []byte(`{"name":"john","score":100}`)
    json.Unmarshal(s, &m)
    fmt.Println(m.Map())
}

After execution, the output is:

map[name:john score:100]

Map - Usage

Map - Usage

Concurrent Safety

Usage Example

Basic Usage

Ordered Traversal

FilterEmpty/FilterNil Empty Value Filtering

Flip Key-Value Pair Reversal

Keys/Values Key/Value Lists

Pop/Pops Random Pop

SetIfNotExist* Conditional Setting

Merge Dictionary Merge

JSON Serialization/Deserialization

`FilterEmpty/FilterNil` Empty Value Filtering

`Flip` Key-Value Pair Reversal

`Keys/Values` Key/Value Lists

`Pop/Pops` Random Pop

`SetIfNotExist*` Conditional Setting

`Merge` Dictionary Merge

`JSON` Serialization/Deserialization