Sync.map of go language

brief introduction
go The language comes with map, Not thread safe ; So in order to achieve thread safety , have access to sync.Map
See the following code for specific examples

package main

import (
    "fmt"
    "sync"
)

func main() {
    var testMap sync.Map

    // obtain a The corresponding key value should fail
    valueA,ok := testMap.Load("a")
    if ok {
        fmt.Println("a", valueA)
    } else {
        fmt.Println("a no value" ) // true
    }

    // Set up a Corresponding key value , And then get
    testMap.Store("a", "ok1")
    valueA,ok = testMap.Load("a")
    if ok {
        fmt.Println("a", valueA) // true
    } else {
        fmt.Println("a no value")
    }

    // Set up a Corresponding key value , And then get
    testMap.Store("a", "ok2")
    valueA,ok = testMap.Load("a")
    if ok {
        fmt.Println("a", valueA) // true
    } else {
        fmt.Println("a no value")
    }

    // Set up a Corresponding key value , And then get
    // if a Corresponding key value exists , Just get , Do not set new values
    valueA,ok = testMap.LoadOrStore("a", "ok3")
    if ok {
        fmt.Println("a", valueA) // true
    } else {
        fmt.Println("a no value")
    }
    valueA,ok = testMap.Load("a")
    if ok {
        fmt.Println("a", valueA) // true
    } else {
        fmt.Println("a no value")
    }
    // if a There is no corresponding key value , Then set
    valueB,ok := testMap.LoadOrStore("b", "ok3")
    if ok {
        fmt.Println("b", valueB)
    } else {
        fmt.Println("b no value") // true
    }
    valueB,ok = testMap.Load("b")
    if ok {
        fmt.Println("b", valueB) // true
    } else {
        fmt.Println("b no value")
    }

    // Traverse
    testMap.Range(func(key, value interface{}) bool {
        keyInfo := key.(string)
        valueInfo := value.(string)
        fmt.Println("keyInfo", keyInfo, "valueInfo", valueInfo)
        return true
    })

    // Delete
    testMap.Delete("a")
}

Running results

a no value
a ok1
a ok2
a ok2
a ok2
b no value
b ok3
keyInfo a valueInfo ok2
keyInfo b valueInfo ok3
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