// Copyright 2013 The Go Authors. All rights reserved. // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. package regexp_test import ( "fmt" "regexp" "strings" ) func Example() { // Compile the expression once, usually at init time. // Use raw strings to avoid having to quote the backslashes. var validID = regexp.MustCompile(`^[a-z]+\[[0-9]+\]$`) fmt.Println(validID.MatchString("adam[23]")) fmt.Println(validID.MatchString("eve[7]")) fmt.Println(validID.MatchString("Job[48]")) fmt.Println(validID.MatchString("snakey")) // Output: // true // true // false // false } func ExampleMatch() { matched, err := regexp.Match(`foo.*`, []byte(`seafood`)) fmt.Println(matched, err) matched, err = regexp.Match(`bar.*`, []byte(`seafood`)) fmt.Println(matched, err) matched, err = regexp.Match(`a(b`, []byte(`seafood`)) fmt.Println(matched, err) // Output: // true // false // false error parsing regexp: missing closing ): `a(b` } func ExampleMatchString() { matched, err := regexp.MatchString(`foo.*`, "seafood") fmt.Println(matched, err) matched, err = regexp.MatchString(`bar.*`, "seafood") fmt.Println(matched, err) matched, err = regexp.MatchString(`a(b`, "seafood") fmt.Println(matched, err) // Output: // true // false // false error parsing regexp: missing closing ): `a(b` } func ExampleQuoteMeta() { fmt.Println(regexp.QuoteMeta(`Escaping symbols like: .+*?()|[]{}^$`)) // Output: // Escaping symbols like: \.\+\*\?\(\)\|\[\]\{\}\^\$ } func ExampleRegexp_Find() { re := regexp.MustCompile(`foo.?`) fmt.Printf("%q\n", re.Find([]byte(`seafood fool`))) // Output: // "food" } func ExampleRegexp_FindAll() { re := regexp.MustCompile(`foo.?`) fmt.Printf("%q\n", re.FindAll([]byte(`seafood fool`), -1)) // Output: // ["food" "fool"] } func ExampleRegexp_FindAllSubmatch() { re := regexp.MustCompile(`foo(.?)`) fmt.Printf("%q\n", re.FindAllSubmatch([]byte(`seafood fool`), -1)) // Output: // [["food" "d"] ["fool" "l"]] } func ExampleRegexp_FindSubmatch() { re := regexp.MustCompile(`foo(.?)`) fmt.Printf("%q\n", re.FindSubmatch([]byte(`seafood fool`))) // Output: // ["food" "d"] } func ExampleRegexp_Match() { re := regexp.MustCompile(`foo.?`) fmt.Println(re.Match([]byte(`seafood fool`))) fmt.Println(re.Match([]byte(`something else`))) // Output: // true // false } func ExampleRegexp_FindString() { re := regexp.MustCompile(`foo.?`) fmt.Printf("%q\n", re.FindString("seafood fool")) fmt.Printf("%q\n", re.FindString("meat")) // Output: // "food" // "" } func ExampleRegexp_FindStringIndex() { re := regexp.MustCompile(`ab?`) fmt.Println(re.FindStringIndex("tablett")) fmt.Println(re.FindStringIndex("foo") == nil) // Output: // [1 3] // true } func ExampleRegexp_FindStringSubmatch() { re := regexp.MustCompile(`a(x*)b(y|z)c`) fmt.Printf("%q\n", re.FindStringSubmatch("-axxxbyc-")) fmt.Printf("%q\n", re.FindStringSubmatch("-abzc-")) // Output: // ["axxxbyc" "xxx" "y"] // ["abzc" "" "z"] } func ExampleRegexp_FindAllString() { 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)) // Output: // [ar an al] // [ar an] // [aa] // [] } func ExampleRegexp_FindAllStringSubmatch() { re := regexp.MustCompile(`a(x*)b`) fmt.Printf("%q\n", re.FindAllStringSubmatch("-ab-", -1)) fmt.Printf("%q\n", re.FindAllStringSubmatch("-axxb-", -1)) fmt.Printf("%q\n", re.FindAllStringSubmatch("-ab-axb-", -1)) fmt.Printf("%q\n", re.FindAllStringSubmatch("-axxb-ab-", -1)) // Output: // [["ab" ""]] // [["axxb" "xx"]] // [["ab" ""] ["axb" "x"]] // [["axxb" "xx"] ["ab" ""]] } func ExampleRegexp_FindAllStringSubmatchIndex() { re := regexp.MustCompile(`a(x*)b`) // Indices: // 01234567 012345678 // -ab-axb- -axxb-ab- fmt.Println(re.FindAllStringSubmatchIndex("-ab-", -1)) fmt.Println(re.FindAllStringSubmatchIndex("-axxb-", -1)) fmt.Println(re.FindAllStringSubmatchIndex("-ab-axb-", -1)) fmt.Println(re.FindAllStringSubmatchIndex("-axxb-ab-", -1)) fmt.Println(re.FindAllStringSubmatchIndex("-foo-", -1)) // Output: // [[1 3 2 2]] // [[1 5 2 4]] // [[1 3 2 2] [4 7 5 6]] // [[1 5 2 4] [6 8 7 7]] // [] } func ExampleRegexp_FindSubmatchIndex() { re := regexp.MustCompile(`a(x*)b`) // Indices: // 01234567 012345678 // -ab-axb- -axxb-ab- fmt.Println(re.FindSubmatchIndex([]byte("-ab-"))) fmt.Println(re.FindSubmatchIndex([]byte("-axxb-"))) fmt.Println(re.FindSubmatchIndex([]byte("-ab-axb-"))) fmt.Println(re.FindSubmatchIndex([]byte("-axxb-ab-"))) fmt.Println(re.FindSubmatchIndex([]byte("-foo-"))) // Output: // [1 3 2 2] // [1 5 2 4] // [1 3 2 2] // [1 5 2 4] // [] } func ExampleRegexp_Longest() { re := regexp.MustCompile(`a(|b)`) fmt.Println(re.FindString("ab")) re.Longest() fmt.Println(re.FindString("ab")) // Output: // a // ab } func ExampleRegexp_MatchString() { re := regexp.MustCompile(`(gopher){2}`) fmt.Println(re.MatchString("gopher")) fmt.Println(re.MatchString("gophergopher")) fmt.Println(re.MatchString("gophergophergopher")) // Output: // false // true // true } func ExampleRegexp_NumSubexp() { re0 := regexp.MustCompile(`a.`) fmt.Printf("%d\n", re0.NumSubexp()) re := regexp.MustCompile(`(.*)((a)b)(.*)a`) fmt.Println(re.NumSubexp()) // Output: // 0 // 4 } func ExampleRegexp_ReplaceAll() { re := regexp.MustCompile(`a(x*)b`) fmt.Printf("%s\n", re.ReplaceAll([]byte("-ab-axxb-"), []byte("T"))) fmt.Printf("%s\n", re.ReplaceAll([]byte("-ab-axxb-"), []byte("$1"))) fmt.Printf("%s\n", re.ReplaceAll([]byte("-ab-axxb-"), []byte("$1W"))) fmt.Printf("%s\n", re.ReplaceAll([]byte("-ab-axxb-"), []byte("${1}W"))) re2 := regexp.MustCompile(`a(?P<1W>x*)b`) fmt.Printf("%s\n", re2.ReplaceAll([]byte("-ab-axxb-"), []byte("$1W"))) fmt.Printf("%s\n", re2.ReplaceAll([]byte("-ab-axxb-"), []byte("${1}W"))) // Output: // -T-T- // --xx- // --- // -W-xxW- // --xx- // -W-xxW- } func ExampleRegexp_ReplaceAllLiteralString() { re := regexp.MustCompile(`a(x*)b`) fmt.Println(re.ReplaceAllLiteralString("-ab-axxb-", "T")) fmt.Println(re.ReplaceAllLiteralString("-ab-axxb-", "$1")) fmt.Println(re.ReplaceAllLiteralString("-ab-axxb-", "${1}")) // Output: // -T-T- // -$1-$1- // -${1}-${1}- } func ExampleRegexp_ReplaceAllString() { re := regexp.MustCompile(`a(x*)b`) fmt.Println(re.ReplaceAllString("-ab-axxb-", "T")) fmt.Println(re.ReplaceAllString("-ab-axxb-", "$1")) fmt.Println(re.ReplaceAllString("-ab-axxb-", "$1W")) fmt.Println(re.ReplaceAllString("-ab-axxb-", "${1}W")) re2 := regexp.MustCompile(`a(?P<1W>x*)b`) fmt.Printf("%s\n", re2.ReplaceAllString("-ab-axxb-", "$1W")) fmt.Println(re.ReplaceAllString("-ab-axxb-", "${1}W")) // Output: // -T-T- // --xx- // --- // -W-xxW- // --xx- // -W-xxW- } func ExampleRegexp_ReplaceAllStringFunc() { re := regexp.MustCompile(`[^aeiou]`) fmt.Println(re.ReplaceAllStringFunc("seafood fool", strings.ToUpper)) // Output: // SeaFooD FooL } func ExampleRegexp_SubexpNames() { re := regexp.MustCompile(`(?P[a-zA-Z]+) (?P[a-zA-Z]+)`) fmt.Println(re.MatchString("Alan Turing")) fmt.Printf("%q\n", re.SubexpNames()) reversed := fmt.Sprintf("${%s} ${%s}", re.SubexpNames()[2], re.SubexpNames()[1]) fmt.Println(reversed) fmt.Println(re.ReplaceAllString("Alan Turing", reversed)) // Output: // true // ["" "first" "last"] // ${last} ${first} // Turing Alan } func ExampleRegexp_SubexpIndex() { re := regexp.MustCompile(`(?P[a-zA-Z]+) (?P[a-zA-Z]+)`) fmt.Println(re.MatchString("Alan Turing")) matches := re.FindStringSubmatch("Alan Turing") lastIndex := re.SubexpIndex("last") fmt.Printf("last => %d\n", lastIndex) fmt.Println(matches[lastIndex]) // Output: // true // last => 2 // Turing } func ExampleRegexp_Split() { a := regexp.MustCompile(`a`) fmt.Println(a.Split("banana", -1)) fmt.Println(a.Split("banana", 0)) fmt.Println(a.Split("banana", 1)) fmt.Println(a.Split("banana", 2)) zp := regexp.MustCompile(`z+`) fmt.Println(zp.Split("pizza", -1)) fmt.Println(zp.Split("pizza", 0)) fmt.Println(zp.Split("pizza", 1)) fmt.Println(zp.Split("pizza", 2)) // Output: // [b n n ] // [] // [banana] // [b nana] // [pi a] // [] // [pizza] // [pi a] } func ExampleRegexp_Expand() { content := []byte(` # comment line option1: value1 option2: value2 # another comment line option3: value3 `) // Regex pattern captures "key: value" pair from the content. pattern := regexp.MustCompile(`(?m)(?P\w+):\s+(?P\w+)$`) // Template to convert "key: value" to "key=value" by // referencing the values captured by the regex pattern. template := []byte("$key=$value\n") result := []byte{} // For each match of the regex in the content. for _, submatches := range pattern.FindAllSubmatchIndex(content, -1) { // Apply the captured submatches to the template and append the output // to the result. result = pattern.Expand(result, template, content, submatches) } fmt.Println(string(result)) // Output: // option1=value1 // option2=value2 // option3=value3 } func ExampleRegexp_ExpandString() { content := ` # comment line option1: value1 option2: value2 # another comment line option3: value3 ` // Regex pattern captures "key: value" pair from the content. pattern := regexp.MustCompile(`(?m)(?P\w+):\s+(?P\w+)$`) // Template to convert "key: value" to "key=value" by // referencing the values captured by the regex pattern. template := "$key=$value\n" result := []byte{} // For each match of the regex in the content. for _, submatches := range pattern.FindAllStringSubmatchIndex(content, -1) { // Apply the captured submatches to the template and append the output // to the result. result = pattern.ExpandString(result, template, content, submatches) } fmt.Println(string(result)) // Output: // option1=value1 // option2=value2 // option3=value3 } func ExampleRegexp_FindIndex() { content := []byte(` # comment line option1: value1 option2: value2 `) // Regex pattern captures "key: value" pair from the content. pattern := regexp.MustCompile(`(?m)(?P\w+):\s+(?P\w+)$`) loc := pattern.FindIndex(content) fmt.Println(loc) fmt.Println(string(content[loc[0]:loc[1]])) // Output: // [18 33] // option1: value1 } func ExampleRegexp_FindAllSubmatchIndex() { content := []byte(` # comment line option1: value1 option2: value2 `) // Regex pattern captures "key: value" pair from the content. pattern := regexp.MustCompile(`(?m)(?P\w+):\s+(?P\w+)$`) allIndexes := pattern.FindAllSubmatchIndex(content, -1) for _, loc := range allIndexes { fmt.Println(loc) fmt.Println(string(content[loc[0]:loc[1]])) fmt.Println(string(content[loc[2]:loc[3]])) fmt.Println(string(content[loc[4]:loc[5]])) } // Output: // [18 33 18 25 27 33] // option1: value1 // option1 // value1 // [35 50 35 42 44 50] // option2: value2 // option2 // value2 } func ExampleRegexp_FindAllIndex() { content := []byte("London") re := regexp.MustCompile(`o.`) fmt.Println(re.FindAllIndex(content, 1)) fmt.Println(re.FindAllIndex(content, -1)) // Output: // [[1 3]] // [[1 3] [4 6]] }