The strconv package, a type conversion tool package in Go language

##This time let’s learn a type of Go language Converttoolkitstrconv.

I don’t know if you have thought about it.

In Go, How to convert the string 100 into the number 100.

so?

func main() {
    var score = "100"
    i := int(score)
    fmt.Printf(i)
}

No, No, No, look at the execution results.

An error has been reported, indicating that it is not such a simple and crude conversion! ! !

String to int (using Atoi)

Code

func main() {
    //string 100
    var scoreStr = "100"
    fmt.Printf("%v，%T\n"， scoreStr， scoreStr) //100，string
    score， err := strconv.Atoi(scoreStr)
    //转换失败
    if err != nil {
        panic(err)
}
    fmt.Printf("%v，%T\n"， score， score)
}

Execution results

It can be found that the conversion was successful After that, it became the int type.

int转string(用Itoa)

代码

func main() {
    //int 100
    var scoreInt = 100
    fmt.Printf("%v，%T\n"， scoreInt， scoreInt) //100，string
    score  := strconv.Itoa(scoreInt)
    fmt.Printf("%v，%T\n"， score， score)
}

执行结果

注:在Go中，只能通过上述两种方式进行string -> int，int -> string。

strconv.Parse converts

##strconv to ParseRelated methods also talk about converting string type to other types, but in comparison.

strconv will have more diversity in Parse a little.

strconv.ParseBool()

This method is to convert the Bool of the string type, converted to the real Bool type.

示例代码

func main() {
    var tString = "true"//可以是 1，0，t，f，T，F，true，false，True，False，TRUE，FALSE
    fmt.Printf("%T，%v\n"， tString， tString)
    tBool， err := strconv.ParseBool(tString)
    if err != nil {
        panic(err)
}
    fmt.Printf("%T，%v\n"， tBool， tBool)
}

执行结果

成功将字符串true转成Bool true。

strconv.ParseInt()

这个，就很简单了，跟strconv.Atoi()基本一样。

示例代码

func main() {
   var tString = "666"
   fmt.Printf("%T，%v\n"， tString， tString)
   tInt， err := strconv.ParseInt(tString，10，64)
   if err != nil {
      panic(err)
   }
   fmt.Printf("%T，%v\n"， tInt， tInt)
}

执行结果

第二个参数10和第三个参数64的意思。

Maybe you are like me and didn’t understand the second parameter 10 and the first The meaning of the three parameters 64.

But you may understand the picture below.

Just understand it. Under normal circumstances, just write the above code. It is originally converted to int , why do you think so much! ! !

strconv.parseUint()

Same as above, but this can only convert positive numbers , cannot convert negative numbers.

strconv.ParseFloat()

This, as you can see from the name, converts string to floating point number TransferReal floating point number.

示例代码

func main() {
    var tString = "3.1415"
    fmt.Printf("%T，%v\n"， tString， tString)
    tFloat， err := strconv.ParseFloat(tString，64)
    if err != nil {
        panic(err)
}
    fmt.Printf("%T，%v\n"， tFloat， tFloat)
}

第二个参数64，同上，也是因为返回的就是float64，所以容量也得是64。

执行结果

strconv.Format转换

这个和strconv.Parse是相反的，是将int/float/bool等 -> string的一个过程。

但是我总感觉有点脱裤子放屁的感觉，既然官方提供了，就随便看看叭！！！

这里我就使用简述的代码来写的。

func main() {
    a := strconv.FormatBool(true)
    //E表示十进制，
    b := strconv.FormatFloat(3.1415， 'E'， -1， 64)
    c := strconv.FormatInt(666， 10)
    fmt.Printf("%v，%T\n"，a，a)
    fmt.Printf("%v，%T\n"，b，b)
    fmt.Printf("%v，%T\n"，c，c)
}

执行结果

总结

其实这次我们的重点主要是前俩，string - > int(用Atoi)，int -> string(用Itoa)。

其他的主要分为strconv.Parse系列和strconv.Format系列。

Relatively speaking, Parse series may be used more, Format There are not too many related uses, just understand it!

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