splitx.go

package stringsplus

import (
    "strings"
)

// SplitX works similarly to strings.SplitN except instead of splitting into
// a given number of strings it splits on the given index of the split string.
func SplitX(s, sep string, x int) []string {
    return splitX(s, sep, 0, x)
}

// SplitAfterX works similarly to SplitX except it will split after the separator.
func SplitAfterX(s, sep string, x int) []string {
    return splitX(s, sep, len(sep), x)
}

func splitX(s, sep string, sepSave, x int) []string {
    // Implementation is based off strings genSplit.
    if x == 0 {
        return nil
    }
    if sep == "" {
        panic("Not implemented, see strings explode")
    }
    // TODO: not sure this is needed or wanted behavior lol
    if x < 0 {
        x = strings.Count(s, sep) + 1
    }
    c := sep[0]
    start := 0
    a := make([]string, 2)
    count := 0
    xa := 0
    for i := 0; i+len(sep) <= len(s) && xa+1 < x; i++ {
        if s[i] == c && (len(sep) == 1 || s[i:i+len(sep)] == sep) {
            count++
            if count == x {
                a[xa] = s[start : i+sepSave]
                xa++
                start = i + len(sep)
                i += len(sep) -1
            }
        }
    }
    a[xa] = s[start:]
    return a[0 : xa+1]
}

https://play.golang.org/p/wKohznuskN