Golang converting string to int64
StringGoInt64String Problem Overview
I want to convert a string to an int64. What I find from the strconv
package is the Atoi
function. It seems to cast a string to an int and return it:
// Atoi is shorthand for ParseInt(s, 10, 0).
func Atoi(s string) (i int, err error) {
i64, err := ParseInt(s, 10, 0)
return int(i64), err
}
The ParseInt actually returns an int64:
func ParseInt(s string, base int, bitSize int) (i int64, err error){
//...
}
So if I want to get an int64 from a string, should I avoid using Atoi, instead use ParseInt? Or is there an Atio64 hidden somewhere?
String Solutions
Solution 1 - String
Parsing string into int64 example:
// Use the max value for signed 64 integer. http://golang.org/pkg/builtin/#int64
var s string = "9223372036854775807"
i, err := strconv.ParseInt(s, 10, 64)
if err != nil {
panic(err)
}
fmt.Printf("Hello, %v with type %s!\n", i, reflect.TypeOf(i))
output:
> Hello, 9223372036854775807 with type int64!
Solution 2 - String
No, there's no Atoi64. You should also pass in the 64 as the last parameter to ParseInt, or it might not produce the expected value on a 32-bit system.
Adding abbreviated example:
var s string = "9223372036854775807"
i, _ := strconv.ParseInt(s, 10, 64)
fmt.Printf("val: %v ; type: %[1]T\n", i)
Solution 3 - String
Another option:
package main
import "fmt"
func main() {
var n int64
fmt.Sscan("100", &n)
fmt.Println(n == 100)
}