【Go】int64型・uint64型からstring型へ変換する方法

int64型からstring型へ変換する方法

// int64
var Int64 int64 = 9223372036854775807

// strconv.FormatInt(int64, 基数（10進数）)
convertedInt64 := strconv.FormatInt(Int64, 10)

9223372036854775807はint64の最大数です

int64 is the set of all signed 64-bit integers. Range: -9223372036854775808 through 9223372036854775807.

uint64型からstring型へ変換する方法

// uint64   
var Uint64 uint64 = 18446744073709551615

// strconv.FormatUint(uint64, 基数（10進数）)
convertedUint64 := strconv.FormatUint(Uint64, 10)

18446744073709551615はuint64の最大数です

uint64 is the set of all unsigned 64-bit integers. Range: 0 through 18446744073709551615.

Go Playground

package main

import (
    "strconv"
    "fmt"
    "reflect"
)

func main() {

    var Int64 int64 = 9223372036854775807
    convertedInt64 := strconv.FormatInt(Int64,10)
    fmt.Printf("%v with type %s \n", convertedInt64, reflect.TypeOf(convertedInt64))

    var Uint64 uint64 = 18446744073709551615
    convertedUint64 := strconv.FormatUint(Uint64,10)
    fmt.Printf("%v with type %s \n", convertedUint64, reflect.TypeOf(convertedUint64))
}

実行結果

9223372036854775807 with type string 
18446744073709551615 with type string 

【おまけ】string型からint64・uint64型へ変換からの再びstring型へ変換

package main

import (
    "strconv"
    "fmt"
    "reflect"
)

func main() {
    fmt.Println("\n----- convert String to Int64 and Uint64 -------------------")

    // int64
    var strInt64 string = "9223372036854775807"
    convertedStrInt64, _ := strconv.ParseInt(strInt64, 10, 64)

    fmt.Printf("%v with type %s \n", convertedStrInt64, reflect.TypeOf(convertedStrInt64))

    // uint64   
    var strUint64 string = "18446744073709551615"
    convertedStrUint64, _ := strconv.ParseUint(strUint64, 10, 64)

    fmt.Printf("%v with type %s \n", convertedStrUint64, reflect.TypeOf(convertedStrUint64))

    fmt.Println("\n----- convert Int64 and Uint64 to String -------------------")

    convertedInt64 := strconv.FormatInt(convertedStrInt64,10)
    fmt.Printf("%v with type %s \n", convertedInt64, reflect.TypeOf(convertedInt64))

    convertedUint64 := strconv.FormatUint(convertedStrUint64,10)
    fmt.Printf("%v with type %s \n", convertedUint64, reflect.TypeOf(convertedUint64))
}

実行結果

----- convert String to Int64 and Uint64 -------------------
9223372036854775807 with type int64 
18446744073709551615 with type uint64 

----- convert Int64 and Uint64 to String -------------------
9223372036854775807 with type string 
18446744073709551615 with type string