Examples in Go
Go offers built-in support for regular expressions. Here are some examples of common regexp-related tasks in Go.
package main

import (
    "bytes"
    "fmt"
    "regexp"
)

func main() {

    match, _ := regexp.MatchString("p([a-z]+)ch", "peach")
    fmt.Println(match)

    r, _ := regexp.Compile("p([a-z]+)ch")

    fmt.Println(r.MatchString("peach"))

    fmt.Println(r.FindString("peach punch"))

    fmt.Println(r.FindStringIndex("peach punch"))

    fmt.Println(r.FindStringSubmatch("peach punch"))

    fmt.Println(r.FindStringSubmatchIndex("peach punch"))

    fmt.Println(r.FindAllString("peach punch pinch", -1))

    fmt.Println(r.FindAllStringSubmatchIndex(
        "peach punch pinch", -1))

    fmt.Println(r.FindAllString("peach punch pinch", 2))

    fmt.Println(r.Match([]byte("peach")))

    r = regexp.MustCompile("p([a-z]+)ch")
    fmt.Println(r)

    fmt.Println(r.ReplaceAllString("a peach", ""))

    in := []byte("a peach")
    out := r.ReplaceAllFunc(in, bytes.ToUpper)
    fmt.Println(string(out))
}