golang filter slice

filter_slice.go

// remember that "slice magic" means that the underlying array of data 
// beyond the 'i'th value may still be available, so the slice should not
// be exported outside of the package, like to third-party software

func demoFilter(s []int) []int {
    i := 0
    for _, v := range s {
        if v > 1 { // some criteria; this is the filter
            s[i] = v
            i++
        }
    }
    return s[:i]
}

func demoMain() {
    x := demoFilter([]int{1,2,3,0,1,8,9})
    fmt.Println(x)
}

// out: [2 3 8 9]