Go regular expression matches strings, replaces strings

package main

import (
    "fmt"
    "regexp"
)

func main() {
    match, err := ("h[a-z]+.*d$", "hello world")
    if err != nil {
        panic(err)
    }
    (match)

    match, err = ("h[a-z]+.*d$", "ello world")
    if err != nil {
        panic(err)
    }
    (match)
}

// $ go run 
// The output is as follows/**
  true
  false
*/

package main

import (
    "fmt"
    "regexp"
)

func main() {
    c, err := ("h[a-z]")
    if err != nil {
        panic(err)
    }

    res := ("hello world", -1)
    ("res = %v\n", res)

    res2 := ("hello world hi ha h1", -1)
    ("res2 = %v\n", res2)
}

// $ go run 
// The output is as follows/**
  res = [he]
  res2 = [he hi ha]
*/

package main

import (
    "fmt"
    "regexp"
)

func main() {
    c, err := ("h[a-z]")
    if err != nil {
        panic(err)
    }

    res := ([]byte("hello world"), []byte("?"))
    ("res = %s\n", res)

    res2 := ([]byte("hello world hi ha h1"), []byte("?"))
    ("res2 = %s\n", res2)
}

// $ go run 
// The output is as follows/**
  res = ?llo world
  res2 = ?llo world ? ? h1
*/

package main

import (
    "fmt"
    "regexp"
)

func main() {
    match, err := ("\\x{4e00}-\\x{9fa5}", "hello world")
    if err != nil {
        panic(err)
    }
    (match)

    match, err = ("\\p{Han}+", "hello world")
    if err != nil {
        panic(err)
    }
    (match)
}

// $ go run 
// The output is as follows/**
  false
  true
*/