Go正則表達式實例

Go提供對正則表達式的內置支持。 下面是Go中常見的regexp相關任務的一些例子。

具體的每個函數，可參考示例中的代碼 -

所有的示例代碼，都放在 F:\worksp\golang 目錄下。安裝Go編程環境請參考：http://www.yiibai.com/go/go\_environment.html

string-formatting.go的完整代碼如下所示 -

package main

import "bytes"
import "fmt"
import "regexp"

func main() {

    // This tests whether a pattern matches a string.
    match, _ := regexp.MatchString("p([a-z]+)ch", "peach")
    fmt.Println(match)

    // Above we used a string pattern directly, but for
    // other regexp tasks you'll need to `Compile` an
    // optimized `Regexp` struct.
    r, _ := regexp.Compile("p([a-z]+)ch")

    // Many methods are available on these structs. Here's
    // a match test like we saw earlier.
    fmt.Println(r.MatchString("peach"))

    // This finds the match for the regexp.
    fmt.Println(r.FindString("peach punch"))

    // This also finds the first match but returns the
    // start and end indexes for the match instead of the
    // matching text.
    fmt.Println(r.FindStringIndex("peach punch"))

    // The `Submatch` variants include information about
    // both the whole-pattern matches and the submatches
    // within those matches. For example this will return
    // information for both `p([a-z]+)ch` and `([a-z]+)`.
    fmt.Println(r.FindStringSubmatch("peach punch"))

    // Similarly this will return information about the
    // indexes of matches and submatches.
    fmt.Println(r.FindStringSubmatchIndex("peach punch"))

    // The `All` variants of these functions apply to all
    // matches in the input, not just the first. For
    // example to find all matches for a regexp.
    fmt.Println(r.FindAllString("peach punch pinch", -1))

    // These `All` variants are available for the other
    // functions we saw above as well.
    fmt.Println(r.FindAllStringSubmatchIndex(
        "peach punch pinch", -1))

    // Providing a non-negative integer as the second
    // argument to these functions will limit the number
    // of matches.
    fmt.Println(r.FindAllString("peach punch pinch", 2))

    // Our examples above had string arguments and used
    // names like `MatchString`. We can also provide
    // `[]byte` arguments and drop `String` from the
    // function name.
    fmt.Println(r.Match([]byte("peach")))

    // When creating constants with regular expressions
    // you can use the `MustCompile` variation of
    // `Compile`. A plain `Compile` won't work for
    // constants because it has 2 return values.
    r = regexp.MustCompile("p([a-z]+)ch")
    fmt.Println(r)

    // The `regexp` package can also be used to replace
    // subsets of strings with other values.
    fmt.Println(r.ReplaceAllString("a peach", "<fruit>"))

    // The `Func` variant allows you to transform matched
    // text with a given function.
    in := []byte("a peach")
    out := r.ReplaceAllFunc(in, bytes.ToUpper)
    fmt.Println(string(out))
}

執行上面代碼，將得到以下輸出結果 -

F:\worksp\golang>go run regular-expressions.go
true
true
peach
[0 5]
[peach ea]
[0 5 1 3]
[peach punch pinch]
[[0 5 1 3] [6 11 7 9] [12 17 13 15]]
[peach punch]
true
p([a-z]+)ch
a <fruit>
a PEACH