2018-05-07 Edward Smith-Rowland <3dw4rd@verizon.net>
[official-gcc.git] / libgo / go / bytes / example_test.go
blob5b7a46058f5c73b44ec111b411d9580ae5c3f7ff
1 // Copyright 2011 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 package bytes_test
7 import (
8 "bytes"
9 "encoding/base64"
10 "fmt"
11 "io"
12 "os"
13 "sort"
14 "unicode"
17 func ExampleBuffer() {
18 var b bytes.Buffer // A Buffer needs no initialization.
19 b.Write([]byte("Hello "))
20 fmt.Fprintf(&b, "world!")
21 b.WriteTo(os.Stdout)
22 // Output: Hello world!
25 func ExampleBuffer_reader() {
26 // A Buffer can turn a string or a []byte into an io.Reader.
27 buf := bytes.NewBufferString("R29waGVycyBydWxlIQ==")
28 dec := base64.NewDecoder(base64.StdEncoding, buf)
29 io.Copy(os.Stdout, dec)
30 // Output: Gophers rule!
33 func ExampleBuffer_Grow() {
34 var b bytes.Buffer
35 b.Grow(64)
36 bb := b.Bytes()
37 b.Write([]byte("64 bytes or fewer"))
38 fmt.Printf("%q", bb[:b.Len()])
39 // Output: "64 bytes or fewer"
42 func ExampleCompare() {
43 // Interpret Compare's result by comparing it to zero.
44 var a, b []byte
45 if bytes.Compare(a, b) < 0 {
46 // a less b
48 if bytes.Compare(a, b) <= 0 {
49 // a less or equal b
51 if bytes.Compare(a, b) > 0 {
52 // a greater b
54 if bytes.Compare(a, b) >= 0 {
55 // a greater or equal b
58 // Prefer Equal to Compare for equality comparisons.
59 if bytes.Equal(a, b) {
60 // a equal b
62 if !bytes.Equal(a, b) {
63 // a not equal b
67 func ExampleCompare_search() {
68 // Binary search to find a matching byte slice.
69 var needle []byte
70 var haystack [][]byte // Assume sorted
71 i := sort.Search(len(haystack), func(i int) bool {
72 // Return haystack[i] >= needle.
73 return bytes.Compare(haystack[i], needle) >= 0
75 if i < len(haystack) && bytes.Equal(haystack[i], needle) {
76 // Found it!
80 func ExampleTrimSuffix() {
81 var b = []byte("Hello, goodbye, etc!")
82 b = bytes.TrimSuffix(b, []byte("goodbye, etc!"))
83 b = bytes.TrimSuffix(b, []byte("gopher"))
84 b = append(b, bytes.TrimSuffix([]byte("world!"), []byte("x!"))...)
85 os.Stdout.Write(b)
86 // Output: Hello, world!
89 func ExampleTrimPrefix() {
90 var b = []byte("Goodbye,, world!")
91 b = bytes.TrimPrefix(b, []byte("Goodbye,"))
92 b = bytes.TrimPrefix(b, []byte("See ya,"))
93 fmt.Printf("Hello%s", b)
94 // Output: Hello, world!
97 func ExampleFields() {
98 fmt.Printf("Fields are: %q", bytes.Fields([]byte(" foo bar baz ")))
99 // Output: Fields are: ["foo" "bar" "baz"]
102 func ExampleFieldsFunc() {
103 f := func(c rune) bool {
104 return !unicode.IsLetter(c) && !unicode.IsNumber(c)
106 fmt.Printf("Fields are: %q", bytes.FieldsFunc([]byte(" foo1;bar2,baz3..."), f))
107 // Output: Fields are: ["foo1" "bar2" "baz3"]
110 func ExampleContains() {
111 fmt.Println(bytes.Contains([]byte("seafood"), []byte("foo")))
112 fmt.Println(bytes.Contains([]byte("seafood"), []byte("bar")))
113 fmt.Println(bytes.Contains([]byte("seafood"), []byte("")))
114 fmt.Println(bytes.Contains([]byte(""), []byte("")))
115 // Output:
116 // true
117 // false
118 // true
119 // true
122 func ExampleContainsAny() {
123 fmt.Println(bytes.ContainsAny([]byte("I like seafood."), "fÄo!"))
124 fmt.Println(bytes.ContainsAny([]byte("I like seafood."), "去是伟大的."))
125 fmt.Println(bytes.ContainsAny([]byte("I like seafood."), ""))
126 fmt.Println(bytes.ContainsAny([]byte(""), ""))
127 // Output:
128 // true
129 // true
130 // false
131 // false
134 func ExampleContainsRune() {
135 fmt.Println(bytes.ContainsRune([]byte("I like seafood."), 'f'))
136 fmt.Println(bytes.ContainsRune([]byte("I like seafood."), 'ö'))
137 fmt.Println(bytes.ContainsRune([]byte("去是伟大的!"), '大'))
138 fmt.Println(bytes.ContainsRune([]byte("去是伟大的!"), '!'))
139 fmt.Println(bytes.ContainsRune([]byte(""), '@'))
140 // Output:
141 // true
142 // false
143 // true
144 // true
145 // false
148 func ExampleCount() {
149 fmt.Println(bytes.Count([]byte("cheese"), []byte("e")))
150 fmt.Println(bytes.Count([]byte("five"), []byte(""))) // before & after each rune
151 // Output:
152 // 3
153 // 5
156 func ExampleEqual() {
157 fmt.Println(bytes.Equal([]byte("Go"), []byte("Go")))
158 fmt.Println(bytes.Equal([]byte("Go"), []byte("C++")))
159 // Output:
160 // true
161 // false
164 func ExampleEqualFold() {
165 fmt.Println(bytes.EqualFold([]byte("Go"), []byte("go")))
166 // Output: true
169 func ExampleHasPrefix() {
170 fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("Go")))
171 fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("C")))
172 fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("")))
173 // Output:
174 // true
175 // false
176 // true
179 func ExampleHasSuffix() {
180 fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("go")))
181 fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("O")))
182 fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("Ami")))
183 fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("")))
184 // Output:
185 // true
186 // false
187 // false
188 // true
191 func ExampleIndex() {
192 fmt.Println(bytes.Index([]byte("chicken"), []byte("ken")))
193 fmt.Println(bytes.Index([]byte("chicken"), []byte("dmr")))
194 // Output:
195 // 4
196 // -1
199 func ExampleIndexByte() {
200 fmt.Println(bytes.IndexByte([]byte("chicken"), byte('k')))
201 fmt.Println(bytes.IndexByte([]byte("chicken"), byte('g')))
202 // Output:
203 // 4
204 // -1
207 func ExampleIndexFunc() {
208 f := func(c rune) bool {
209 return unicode.Is(unicode.Han, c)
211 fmt.Println(bytes.IndexFunc([]byte("Hello, 世界"), f))
212 fmt.Println(bytes.IndexFunc([]byte("Hello, world"), f))
213 // Output:
214 // 7
215 // -1
218 func ExampleIndexAny() {
219 fmt.Println(bytes.IndexAny([]byte("chicken"), "aeiouy"))
220 fmt.Println(bytes.IndexAny([]byte("crwth"), "aeiouy"))
221 // Output:
222 // 2
223 // -1
226 func ExampleIndexRune() {
227 fmt.Println(bytes.IndexRune([]byte("chicken"), 'k'))
228 fmt.Println(bytes.IndexRune([]byte("chicken"), 'd'))
229 // Output:
230 // 4
231 // -1
234 func ExampleLastIndex() {
235 fmt.Println(bytes.Index([]byte("go gopher"), []byte("go")))
236 fmt.Println(bytes.LastIndex([]byte("go gopher"), []byte("go")))
237 fmt.Println(bytes.LastIndex([]byte("go gopher"), []byte("rodent")))
238 // Output:
239 // 0
240 // 3
241 // -1
244 func ExampleLastIndexAny() {
245 fmt.Println(bytes.LastIndexAny([]byte("go gopher"), "MüQp"))
246 fmt.Println(bytes.LastIndexAny([]byte("go 地鼠"), "地大"))
247 fmt.Println(bytes.LastIndexAny([]byte("go gopher"), "z,!."))
248 // Output:
249 // 5
250 // 3
251 // -1
254 func ExampleLastIndexByte() {
255 fmt.Println(bytes.LastIndexByte([]byte("go gopher"), byte('g')))
256 fmt.Println(bytes.LastIndexByte([]byte("go gopher"), byte('r')))
257 fmt.Println(bytes.LastIndexByte([]byte("go gopher"), byte('z')))
258 // Output:
259 // 3
260 // 8
261 // -1
264 func ExampleLastIndexFunc() {
265 fmt.Println(bytes.LastIndexFunc([]byte("go gopher!"), unicode.IsLetter))
266 fmt.Println(bytes.LastIndexFunc([]byte("go gopher!"), unicode.IsPunct))
267 fmt.Println(bytes.LastIndexFunc([]byte("go gopher!"), unicode.IsNumber))
268 // Output:
269 // 8
270 // 9
271 // -1
274 func ExampleJoin() {
275 s := [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}
276 fmt.Printf("%s", bytes.Join(s, []byte(", ")))
277 // Output: foo, bar, baz
280 func ExampleRepeat() {
281 fmt.Printf("ba%s", bytes.Repeat([]byte("na"), 2))
282 // Output: banana
285 func ExampleReplace() {
286 fmt.Printf("%s\n", bytes.Replace([]byte("oink oink oink"), []byte("k"), []byte("ky"), 2))
287 fmt.Printf("%s\n", bytes.Replace([]byte("oink oink oink"), []byte("oink"), []byte("moo"), -1))
288 // Output:
289 // oinky oinky oink
290 // moo moo moo
293 func ExampleRunes() {
294 rs := bytes.Runes([]byte("go gopher"))
295 for _, r := range rs {
296 fmt.Printf("%#U\n", r)
298 // Output:
299 // U+0067 'g'
300 // U+006F 'o'
301 // U+0020 ' '
302 // U+0067 'g'
303 // U+006F 'o'
304 // U+0070 'p'
305 // U+0068 'h'
306 // U+0065 'e'
307 // U+0072 'r'
310 func ExampleSplit() {
311 fmt.Printf("%q\n", bytes.Split([]byte("a,b,c"), []byte(",")))
312 fmt.Printf("%q\n", bytes.Split([]byte("a man a plan a canal panama"), []byte("a ")))
313 fmt.Printf("%q\n", bytes.Split([]byte(" xyz "), []byte("")))
314 fmt.Printf("%q\n", bytes.Split([]byte(""), []byte("Bernardo O'Higgins")))
315 // Output:
316 // ["a" "b" "c"]
317 // ["" "man " "plan " "canal panama"]
318 // [" " "x" "y" "z" " "]
319 // [""]
322 func ExampleSplitN() {
323 fmt.Printf("%q\n", bytes.SplitN([]byte("a,b,c"), []byte(","), 2))
324 z := bytes.SplitN([]byte("a,b,c"), []byte(","), 0)
325 fmt.Printf("%q (nil = %v)\n", z, z == nil)
326 // Output:
327 // ["a" "b,c"]
328 // [] (nil = true)
331 func ExampleSplitAfter() {
332 fmt.Printf("%q\n", bytes.SplitAfter([]byte("a,b,c"), []byte(",")))
333 // Output: ["a," "b," "c"]
336 func ExampleSplitAfterN() {
337 fmt.Printf("%q\n", bytes.SplitAfterN([]byte("a,b,c"), []byte(","), 2))
338 // Output: ["a," "b,c"]
341 func ExampleTitle() {
342 fmt.Printf("%s", bytes.Title([]byte("her royal highness")))
343 // Output: Her Royal Highness
346 func ExampleToTitle() {
347 fmt.Printf("%s\n", bytes.ToTitle([]byte("loud noises")))
348 fmt.Printf("%s\n", bytes.ToTitle([]byte("хлеб")))
349 // Output:
350 // LOUD NOISES
351 // ХЛЕБ
354 func ExampleTrim() {
355 fmt.Printf("[%q]", bytes.Trim([]byte(" !!! Achtung! Achtung! !!! "), "! "))
356 // Output: ["Achtung! Achtung"]
359 func ExampleTrimFunc() {
360 fmt.Println(string(bytes.TrimFunc([]byte("go-gopher!"), unicode.IsLetter)))
361 fmt.Println(string(bytes.TrimFunc([]byte("\"go-gopher!\""), unicode.IsLetter)))
362 fmt.Println(string(bytes.TrimFunc([]byte("go-gopher!"), unicode.IsPunct)))
363 fmt.Println(string(bytes.TrimFunc([]byte("1234go-gopher!567"), unicode.IsNumber)))
364 // Output:
365 // -gopher!
366 // "go-gopher!"
367 // go-gopher
368 // go-gopher!
371 func ExampleMap() {
372 rot13 := func(r rune) rune {
373 switch {
374 case r >= 'A' && r <= 'Z':
375 return 'A' + (r-'A'+13)%26
376 case r >= 'a' && r <= 'z':
377 return 'a' + (r-'a'+13)%26
379 return r
381 fmt.Printf("%s", bytes.Map(rot13, []byte("'Twas brillig and the slithy gopher...")))
382 // Output: 'Gjnf oevyyvt naq gur fyvgul tbcure...
385 func ExampleTrimLeft() {
386 fmt.Print(string(bytes.TrimLeft([]byte("453gopher8257"), "0123456789")))
387 // Output:
388 // gopher8257
391 func ExampleTrimLeftFunc() {
392 fmt.Println(string(bytes.TrimLeftFunc([]byte("go-gopher"), unicode.IsLetter)))
393 fmt.Println(string(bytes.TrimLeftFunc([]byte("go-gopher!"), unicode.IsPunct)))
394 fmt.Println(string(bytes.TrimLeftFunc([]byte("1234go-gopher!567"), unicode.IsNumber)))
395 // Output:
396 // -gopher
397 // go-gopher!
398 // go-gopher!567
401 func ExampleTrimSpace() {
402 fmt.Printf("%s", bytes.TrimSpace([]byte(" \t\n a lone gopher \n\t\r\n")))
403 // Output: a lone gopher
406 func ExampleTrimRight() {
407 fmt.Print(string(bytes.TrimRight([]byte("453gopher8257"), "0123456789")))
408 // Output:
409 // 453gopher
412 func ExampleTrimRightFunc() {
413 fmt.Println(string(bytes.TrimRightFunc([]byte("go-gopher"), unicode.IsLetter)))
414 fmt.Println(string(bytes.TrimRightFunc([]byte("go-gopher!"), unicode.IsPunct)))
415 fmt.Println(string(bytes.TrimRightFunc([]byte("1234go-gopher!567"), unicode.IsNumber)))
416 // Output:
417 // go-
418 // go-gopher
419 // 1234go-gopher!
422 func ExampleToUpper() {
423 fmt.Printf("%s", bytes.ToUpper([]byte("Gopher")))
424 // Output: GOPHER
427 func ExampleToLower() {
428 fmt.Printf("%s", bytes.ToLower([]byte("Gopher")))
429 // Output: gopher
432 func ExampleReader_Len() {
433 fmt.Println(bytes.NewReader([]byte("Hi!")).Len())
434 fmt.Println(bytes.NewReader([]byte("こんにちは!")).Len())
435 // Output:
436 // 3
437 // 16