github.com/MangoDowner/go-gm@v0.0.0-20180818020936-8baa2bd4408c/src/bytes/example_test.go (about)

     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 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"
    40  }
    41  
    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
    47  	}
    48  	if bytes.Compare(a, b) <= 0 {
    49  		// a less or equal b
    50  	}
    51  	if bytes.Compare(a, b) > 0 {
    52  		// a greater b
    53  	}
    54  	if bytes.Compare(a, b) >= 0 {
    55  		// a greater or equal b
    56  	}
    57  
    58  	// Prefer Equal to Compare for equality comparisons.
    59  	if bytes.Equal(a, b) {
    60  		// a equal b
    61  	}
    62  	if !bytes.Equal(a, b) {
    63  		// a not equal b
    64  	}
    65  }
    66  
    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
    74  	})
    75  	if i < len(haystack) && bytes.Equal(haystack[i], needle) {
    76  		// Found it!
    77  	}
    78  }
    79  
    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!
    87  }
    88  
    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!
    95  }
    96  
    97  func ExampleFields() {
    98  	fmt.Printf("Fields are: %q", bytes.Fields([]byte("  foo bar  baz   ")))
    99  	// Output: Fields are: ["foo" "bar" "baz"]
   100  }
   101  
   102  func ExampleFieldsFunc() {
   103  	f := func(c rune) bool {
   104  		return !unicode.IsLetter(c) && !unicode.IsNumber(c)
   105  	}
   106  	fmt.Printf("Fields are: %q", bytes.FieldsFunc([]byte("  foo1;bar2,baz3..."), f))
   107  	// Output: Fields are: ["foo1" "bar2" "baz3"]
   108  }
   109  
   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
   120  }
   121  
   122  func ExampleCount() {
   123  	fmt.Println(bytes.Count([]byte("cheese"), []byte("e")))
   124  	fmt.Println(bytes.Count([]byte("five"), []byte(""))) // before & after each rune
   125  	// Output:
   126  	// 3
   127  	// 5
   128  }
   129  
   130  func ExampleEqualFold() {
   131  	fmt.Println(bytes.EqualFold([]byte("Go"), []byte("go")))
   132  	// Output: true
   133  }
   134  
   135  func ExampleHasPrefix() {
   136  	fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("Go")))
   137  	fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("C")))
   138  	fmt.Println(bytes.HasPrefix([]byte("Gopher"), []byte("")))
   139  	// Output:
   140  	// true
   141  	// false
   142  	// true
   143  }
   144  
   145  func ExampleHasSuffix() {
   146  	fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("go")))
   147  	fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("O")))
   148  	fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("Ami")))
   149  	fmt.Println(bytes.HasSuffix([]byte("Amigo"), []byte("")))
   150  	// Output:
   151  	// true
   152  	// false
   153  	// false
   154  	// true
   155  }
   156  
   157  func ExampleIndex() {
   158  	fmt.Println(bytes.Index([]byte("chicken"), []byte("ken")))
   159  	fmt.Println(bytes.Index([]byte("chicken"), []byte("dmr")))
   160  	// Output:
   161  	// 4
   162  	// -1
   163  }
   164  
   165  func ExampleIndexFunc() {
   166  	f := func(c rune) bool {
   167  		return unicode.Is(unicode.Han, c)
   168  	}
   169  	fmt.Println(bytes.IndexFunc([]byte("Hello, 世界"), f))
   170  	fmt.Println(bytes.IndexFunc([]byte("Hello, world"), f))
   171  	// Output:
   172  	// 7
   173  	// -1
   174  }
   175  
   176  func ExampleIndexAny() {
   177  	fmt.Println(bytes.IndexAny([]byte("chicken"), "aeiouy"))
   178  	fmt.Println(bytes.IndexAny([]byte("crwth"), "aeiouy"))
   179  	// Output:
   180  	// 2
   181  	// -1
   182  }
   183  
   184  func ExampleIndexRune() {
   185  	fmt.Println(bytes.IndexRune([]byte("chicken"), 'k'))
   186  	fmt.Println(bytes.IndexRune([]byte("chicken"), 'd'))
   187  	// Output:
   188  	// 4
   189  	// -1
   190  }
   191  
   192  func ExampleLastIndex() {
   193  	fmt.Println(bytes.Index([]byte("go gopher"), []byte("go")))
   194  	fmt.Println(bytes.LastIndex([]byte("go gopher"), []byte("go")))
   195  	fmt.Println(bytes.LastIndex([]byte("go gopher"), []byte("rodent")))
   196  	// Output:
   197  	// 0
   198  	// 3
   199  	// -1
   200  }
   201  
   202  func ExampleJoin() {
   203  	s := [][]byte{[]byte("foo"), []byte("bar"), []byte("baz")}
   204  	fmt.Printf("%s", bytes.Join(s, []byte(", ")))
   205  	// Output: foo, bar, baz
   206  }
   207  
   208  func ExampleRepeat() {
   209  	fmt.Printf("ba%s", bytes.Repeat([]byte("na"), 2))
   210  	// Output: banana
   211  }
   212  
   213  func ExampleReplace() {
   214  	fmt.Printf("%s\n", bytes.Replace([]byte("oink oink oink"), []byte("k"), []byte("ky"), 2))
   215  	fmt.Printf("%s\n", bytes.Replace([]byte("oink oink oink"), []byte("oink"), []byte("moo"), -1))
   216  	// Output:
   217  	// oinky oinky oink
   218  	// moo moo moo
   219  }
   220  
   221  func ExampleSplit() {
   222  	fmt.Printf("%q\n", bytes.Split([]byte("a,b,c"), []byte(",")))
   223  	fmt.Printf("%q\n", bytes.Split([]byte("a man a plan a canal panama"), []byte("a ")))
   224  	fmt.Printf("%q\n", bytes.Split([]byte(" xyz "), []byte("")))
   225  	fmt.Printf("%q\n", bytes.Split([]byte(""), []byte("Bernardo O'Higgins")))
   226  	// Output:
   227  	// ["a" "b" "c"]
   228  	// ["" "man " "plan " "canal panama"]
   229  	// [" " "x" "y" "z" " "]
   230  	// [""]
   231  }
   232  
   233  func ExampleSplitN() {
   234  	fmt.Printf("%q\n", bytes.SplitN([]byte("a,b,c"), []byte(","), 2))
   235  	z := bytes.SplitN([]byte("a,b,c"), []byte(","), 0)
   236  	fmt.Printf("%q (nil = %v)\n", z, z == nil)
   237  	// Output:
   238  	// ["a" "b,c"]
   239  	// [] (nil = true)
   240  }
   241  
   242  func ExampleSplitAfter() {
   243  	fmt.Printf("%q\n", bytes.SplitAfter([]byte("a,b,c"), []byte(",")))
   244  	// Output: ["a," "b," "c"]
   245  }
   246  
   247  func ExampleSplitAfterN() {
   248  	fmt.Printf("%q\n", bytes.SplitAfterN([]byte("a,b,c"), []byte(","), 2))
   249  	// Output: ["a," "b,c"]
   250  }
   251  
   252  func ExampleTitle() {
   253  	fmt.Printf("%s", bytes.Title([]byte("her royal highness")))
   254  	// Output: Her Royal Highness
   255  }
   256  
   257  func ExampleToTitle() {
   258  	fmt.Printf("%s\n", bytes.ToTitle([]byte("loud noises")))
   259  	fmt.Printf("%s\n", bytes.ToTitle([]byte("хлеб")))
   260  	// Output:
   261  	// LOUD NOISES
   262  	// ХЛЕБ
   263  }
   264  
   265  func ExampleTrim() {
   266  	fmt.Printf("[%q]", bytes.Trim([]byte(" !!! Achtung! Achtung! !!! "), "! "))
   267  	// Output: ["Achtung! Achtung"]
   268  }
   269  
   270  func ExampleMap() {
   271  	rot13 := func(r rune) rune {
   272  		switch {
   273  		case r >= 'A' && r <= 'Z':
   274  			return 'A' + (r-'A'+13)%26
   275  		case r >= 'a' && r <= 'z':
   276  			return 'a' + (r-'a'+13)%26
   277  		}
   278  		return r
   279  	}
   280  	fmt.Printf("%s", bytes.Map(rot13, []byte("'Twas brillig and the slithy gopher...")))
   281  	// Output: 'Gjnf oevyyvt naq gur fyvgul tbcure...
   282  }
   283  
   284  func ExampleTrimSpace() {
   285  	fmt.Printf("%s", bytes.TrimSpace([]byte(" \t\n a lone gopher \n\t\r\n")))
   286  	// Output: a lone gopher
   287  }
   288  
   289  func ExampleToUpper() {
   290  	fmt.Printf("%s", bytes.ToUpper([]byte("Gopher")))
   291  	// Output: GOPHER
   292  }
   293  
   294  func ExampleToLower() {
   295  	fmt.Printf("%s", bytes.ToLower([]byte("Gopher")))
   296  	// Output: gopher
   297  }