string to number conversion in golang

Question

Golang has strconv library that converts string to int64 and uint64.

However, the rest of integer data types seems to be unsupported as I can't find conversion functions for byte, int16, uint16, int32, uint32 data types.

One can always convert from byte, 16-bit and 32-bit data types to int64 and uint64 without loss of precision. Is that what's intended by language?

Answer 1

If you look at the docs a bit more closely you can use this method;

func ParseInt(s string, base int, bitSize int)

https://golang.org/pkg/strconv/#ParseInt

The bitSize argument says how large the int is so you can do 8 or 16 or 32 for those smaller integer types. Atoi calls this internally. I believe you're wanting 10 for the base argument. So like b, err := strconv.ParseInt("5", 10, 8) for a byte.

EDIT: Just going to add a couple things to the answer here in case the OP is in fact confused how to convert a 16-bit int into a string... If that is your intended goal just use fmt.Sprintf or you can do a conversion from smaller int to larger int as it will always succeed. Examples of both here;

package main

import "fmt"
import "strconv"

func main() {
    var a int16
    a = 5
    s := fmt.Sprintf("%d", a)
    s2 := strconv.Itoa(int(a))
    fmt.Println(s)
    fmt.Println(s2)
}

Answer 2

For example,

package main

import (
    "fmt"
    "strconv"
)

func main() {
    n := int16(42)
    s := strconv.FormatInt(int64(n), 10)
    fmt.Printf("n %d s %q\n", n, s)
}

Output:

n 42 s "42"