How to compare two version number strings in golang

Question

I have two strings (they are actually version numbers and they could be any version numbers)

a := \"1.05.00.0156\"  
b := \"1.0.221.9289\"

Answer 1

This depends on what you mean by bigger.

A naive approach would be:

package main

import "fmt"
import "strings"

func main() {
    a := strings.Split("1.05.00.0156", ".")
    b := strings.Split("1.0.221.9289", ".")
    for i, s := range a {
        var ai, bi int
        fmt.Sscanf(s, "%d", &ai)
        fmt.Sscanf(b[i], "%d", &bi)
        if ai > bi {
            fmt.Printf("%v is bigger than %v\n", a, b)
            break
        }
        if bi > ai {
            fmt.Printf("%v is bigger than %v\n", b, a)
            break
        }
    }
}

http://play.golang.org/p/j0MtFcn44Z

Answer 2

There is a nice solution from Hashicorp - https://github.com/hashicorp/go-version

import github.com/hashicorp/go-version
v1, err := version.NewVersion("1.2")
v2, err := version.NewVersion("1.5+metadata")
// Comparison example. There is also GreaterThan, Equal, and just
// a simple Compare that returns an int allowing easy >=, <=, etc.
if v1.LessThan(v2) {
    fmt.Printf("%s is less than %s", v1, v2)
}

Answer 3

Some time ago I created a version comparison library: https://github.com/mcuadros/go-version

version.CompareSimple("1.05.00.0156", "1.0.221.9289")
//Returns: 1

Enjoy it!

Answer 4

Based on Jeremy Wall's answer:

  func compareVer(a, b string) (ret int) {
            as := strings.Split(a, ".")
            bs := strings.Split(b, ".")
            loopMax := len(bs)
            if len(as) > len(bs) {
                    loopMax = len(as)
            }
            for i := 0; i < loopMax; i++ { 
                    var x, y string
                    if len(as) > i {
                            x = as[i]
                    }
                    if len(bs) > i {
                            y = bs[i]
                    }
                    xi,_ := strconv.Atoi(x)
                    yi,_ := strconv.Atoi(y)
                    if xi > yi {
                            ret = -1
                    } else if xi < yi {
                            ret = 1
                    }
                    if ret != 0 {
                            break
                    }
            }       
            return 
    }

http://play.golang.org/p/AetJqvFc3B