Regular Expressions
Examples
Filter
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))
}
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)
}
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]
[]
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]]
[]
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