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. 4 5 package bytes_test 6 7 import ( 8 "bytes" 9 "encoding/base64" 10 "fmt" 11 "io" 12 "os" 13 "sort" 14 "unicode" 15 ) 16 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! 23 } 24 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! 31 } 32 33 func ExampleCompare() { 34 // Interpret Compare's result by comparing it to zero. 35 var a, b []byte 36 if bytes.Compare(a, b) < 0 { 37 // a less b 38 } 39 if bytes.Compare(a, b) <= 0 { 40 // a less or equal b 41 } 42 if bytes.Compare(a, b) > 0 { 43 // a greater b 44 } 45 if bytes.Compare(a, b) >= 0 { 46 // a greater or equal b 47 } 48 49 // Prefer Equal to Compare for equality comparisons. 50 if bytes.Equal(a, b) { 51 // a equal b 52 } 53 if !bytes.Equal(a, b) { 54 // a not equal b 55 } 56 } 57 58 func ExampleCompare_search() { 59 // Binary search to find a matching byte slice. 60 var needle []byte 61 var haystack [][]byte // Assume sorted 62 i := sort.Search(len(haystack), func(i int) bool { 63 // Return haystack[i] >= needle. 64 return bytes.Compare(haystack[i], needle) >= 0 65 }) 66 if i < len(haystack) && bytes.Equal(haystack[i], needle) { 67 // Found it! 68 } 69 } 70 71 func ExampleTrimSuffix() { 72 var b = []byte("Hello, goodbye, etc!") 73 b = bytes.TrimSuffix(b, []byte("goodbye, etc!")) 74 b = bytes.TrimSuffix(b, []byte("gopher")) 75 b = append(b, bytes.TrimSuffix([]byte("world!"), []byte("x!"))...) 76 os.Stdout.Write(b) 77 // Output: Hello, world! 78 } 79 80 func ExampleTrimPrefix() { 81 var b = []byte("Goodbye,, world!") 82 b = bytes.TrimPrefix(b, []byte("Goodbye,")) 83 b = bytes.TrimPrefix(b, []byte("See ya,")) 84 fmt.Printf("Hello%s", b) 85 // Output: Hello, world! 86 } 87 88 func ExampleFields() { 89 fmt.Printf("Fields are: %q", bytes.Fields([]byte(" foo bar baz "))) 90 // Output: Fields are: ["foo" "bar" "baz"] 91 } 92 93 func ExampleFieldsFunc() { 94 f := func(c rune) bool { 95 return !unicode.IsLetter(c) && !unicode.IsNumber(c) 96 } 97 fmt.Printf("Fields are: %q", bytes.FieldsFunc([]byte(" foo1;bar2,baz3..."), f)) 98 // Output: Fields are: ["foo1" "bar2" "baz3"] 99 } 100 101 func ExampleContains() { 102 fmt.Println(bytes.Contains([]byte("seafood"), []byte("foo"))) 103 fmt.Println(bytes.Contains([]byte("seafood"), []byte("bar"))) 104 fmt.Println(bytes.Contains([]byte("seafood"), []byte(""))) 105 fmt.Println(bytes.Contains([]byte(""), []byte(""))) 106 // Output: 107 // true 108 // false 109 // true 110 // true 111 } 112 113 func ExampleCount() { 114 fmt.Println(bytes.Count([]byte("cheese"), []byte("e"))) 115 fmt.Println(bytes.Count([]byte("five"), []byte(""))) // before & after each rune 116 // Output: 117 // 3 118 // 5 119 } 120 121 func ExampleEqualFold() { 122 fmt.Println(bytes.EqualFold([]byte("Go"), []byte("go"))) 123 // Output: true 124 } 125 126 func ExampleHasPrefix() { 127 fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("Go"))) 128 fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("C"))) 129 fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte(""))) 130 // Output: 131 // true 132 // false 133 // true 134 } 135 136 func ExampleHasSuffix() { 137 fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("go"))) 138 fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("O"))) 139 fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("Ami"))) 140 fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte(""))) 141 // Output: 142 // true 143 // false 144 // false 145 // true 146 } 147 148 func ExampleIndex() { 149 fmt.Println(bytes.Index([]byte("chicken"), []byte("ken"))) 150 fmt.Println(bytes.Index([]byte("chicken"), []byte("dmr"))) 151 // Output: 152 // 4 153 // -1 154 } 155 156 func ExampleIndexFunc() { 157 f := func(c rune) bool { 158 return unicode.Is(unicode.Han, c) 159 } 160 fmt.Println(bytes.IndexFunc([]byte("Hello, "), f)) 161 fmt.Println(bytes.IndexFunc([]byte("Hello, world"), f)) 162 // Output: 163 // 7 164 // -1 165 } 166 167 func ExampleIndexAny() { 168 fmt.Println(bytes.IndexAny([]byte("chicken"), "aeiouy")) 169 fmt.Println(bytes.IndexAny([]byte("crwth"), "aeiouy")) 170 // Output: 171 // 2 172 // -1 173 } 174 175 func ExampleIndexRune() { 176 fmt.Println(bytes.IndexRune([]byte("chicken"), 'k')) 177 fmt.Println(bytes.IndexRune([]byte("chicken"), 'd')) 178 // Output: 179 // 4 180 // -1 181 } 182 183 func ExampleLastIndex() { 184 fmt.Println(bytes.Index([]byte("go gopher"), []byte("go"))) 185 fmt.Println(bytes.LastIndex([]byte("go gopher"), []byte("go"))) 186 fmt.Println(bytes.LastIndex([]byte("go gopher"), []byte("rodent"))) 187 // Output: 188 // 0 189 // 3 190 // -1 191 } 192 193 func ExampleJoin() { 194 s := [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")} 195 fmt.Printf("%s", bytes.Join(s, []byte(", "))) 196 // Output: foo, bar, baz 197 } 198 199 func ExampleRepeat() { 200 fmt.Printf("ba%s", bytes.Repeat([]byte("na"), 2)) 201 // Output: banana 202 } 203 204 func ExampleReplace() { 205 fmt.Printf("%s\n", bytes.Replace([]byte("oink oink oink"), []byte("k"), []byte("ky"), 2)) 206 fmt.Printf("%s\n", bytes.Replace([]byte("oink oink oink"), []byte("oink"), []byte("moo"), -1)) 207 // Output: 208 // oinky oinky oink 209 // moo moo moo 210 } 211 212 func ExampleSplit() { 213 fmt.Printf("%q\n", bytes.Split([]byte("a,b,c"), []byte(","))) 214 fmt.Printf("%q\n", bytes.Split([]byte("a man a plan a canal panama"), []byte("a "))) 215 fmt.Printf("%q\n", bytes.Split([]byte(" xyz "), []byte(""))) 216 fmt.Printf("%q\n", bytes.Split([]byte(""), []byte("Bernardo O'Higgins"))) 217 // Output: 218 // ["a" "b" "c"] 219 // ["" "man " "plan " "canal panama"] 220 // [" " "x" "y" "z" " "] 221 // [""] 222 } 223 224 func ExampleSplitN() { 225 fmt.Printf("%q\n", bytes.SplitN([]byte("a,b,c"), []byte(","), 2)) 226 z := bytes.SplitN([]byte("a,b,c"), []byte(","), 0) 227 fmt.Printf("%q (nil = %v)\n", z, z == nil) 228 // Output: 229 // ["a" "b,c"] 230 // [] (nil = true) 231 } 232 233 func ExampleSplitAfter() { 234 fmt.Printf("%q\n", bytes.SplitAfter([]byte("a,b,c"), []byte(","))) 235 // Output: ["a," "b," "c"] 236 } 237 238 func ExampleSplitAfterN() { 239 fmt.Printf("%q\n", bytes.SplitAfterN([]byte("a,b,c"), []byte(","), 2)) 240 // Output: ["a," "b,c"] 241 } 242 243 func ExampleTitle() { 244 fmt.Printf("%s", bytes.Title([]byte("her royal highness"))) 245 // Output: Her Royal Highness 246 } 247 248 func ExampleToTitle() { 249 fmt.Printf("%s\n", bytes.ToTitle([]byte("loud noises"))) 250 fmt.Printf("%s\n", bytes.ToTitle([]byte(""))) 251 // Output: 252 // LOUD NOISES 253 // 254 } 255 256 func ExampleTrim() { 257 fmt.Printf("[%q]", bytes.Trim([]byte(" !!! Achtung! Achtung! !!! "), "! ")) 258 // Output: ["Achtung! Achtung"] 259 } 260 261 func ExampleMap() { 262 rot13 := func(r rune) rune { 263 switch { 264 case r >= 'A' && r <= 'Z': 265 return 'A' + (r-'A'+13)%26 266 case r >= 'a' && r <= 'z': 267 return 'a' + (r-'a'+13)%26 268 } 269 return r 270 } 271 fmt.Printf("%s", bytes.Map(rot13, []byte("'Twas brillig and the slithy gopher..."))) 272 // Output: 'Gjnf oevyyvt naq gur fyvgul tbcure... 273 } 274 275 func ExampleTrimSpace() { 276 fmt.Printf("%s", bytes.TrimSpace([]byte(" \t\n a lone gopher \n\t\r\n"))) 277 // Output: a lone gopher 278 } 279 280 func ExampleToUpper() { 281 fmt.Printf("%s", bytes.ToUpper([]byte("Gopher"))) 282 // Output: GOPHER 283 } 284 285 func ExampleToLower() { 286 fmt.Printf("%s", bytes.ToLower([]byte("Gopher"))) 287 // Output: gopher 288 } 289
