Regular Expressions

Post Example
Examples in Go
Regular Expressions in Go
by yhuang Go fmt.Println bytes bytes.ToUpper fmt regexp
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))
}
Match String in Go
by yhuang Go fmt.Println regexp.MatchString fmt regexp 
package main

import (
	"fmt"
	"regexp"
)

func main() {
	matched, err := regexp.MatchString(`foo.*`, "seafood")
	fmt.Println(matched, err)
	matched, err = regexp.MatchString(`bar.*`, "seafood")
	fmt.Println(matched, err)
	matched, err = regexp.MatchString(`a(b`, "seafood")
	fmt.Println(matched, err)
}
Find All Matches in Go
by yhuang Go fmt.Println fmt regexp regexp.MustCompile 
package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`a.`)
	fmt.Println(re.FindAllString("paranormal", -1))
	fmt.Println(re.FindAllString("paranormal", 2))
	fmt.Println(re.FindAllString("graal", -1))
	fmt.Println(re.FindAllString("none", -1))
}

Last Run  :
[ar an al]
[ar an]
[aa]
[]
Find All Matches with Indexes in Go
by yhuang Go fmt.Println fmt regexp regexp.MustCompile 
package main

import (
	"fmt"
	"regexp"
)

func main() {
	re := regexp.MustCompile(`a.`)
	fmt.Println(re.FindAllStringIndex("paranormal", -1))
	fmt.Println(re.FindAllStringIndex("paranormal", 2))
	fmt.Println(re.FindAllStringIndex("graal", -1))
	fmt.Println(re.FindAllStringIndex("none", -1))
}

Last Run  :
[[1 3] [3 5] [8 10]]
[[1 3] [3 5]]
[[2 4]]
[]
Compile Regex in Go
by yhuang Go fmt.Println fmt regexp regexp.MustCompile 
package main

import (
	"fmt"
	"regexp"
)

func main() {
	// Compile the expression once, usually at init time.
	// Use raw strings to avoid having to quote the backslashes.
	var validID = regexp.MustCompile(`^[a-z]+\[[0-9]+\]$`)

	fmt.Println(validID.MatchString("adam[23]"))
	fmt.Println(validID.MatchString("eve[7]"))
	fmt.Println(validID.MatchString("Job[48]"))
	fmt.Println(validID.MatchString("snakey"))
}

Last Run  :
true
true
false
false