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Diffstat (limited to 'dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/rand/example_test.go')
| -rw-r--r-- | dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/rand/example_test.go | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/rand/example_test.go b/dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/rand/example_test.go new file mode 100644 index 0000000..8faad51 --- /dev/null +++ b/dependencies/pkg/mod/golang.org/x/exp@v0.0.0-20220613132600-b0d781184e0d/rand/example_test.go @@ -0,0 +1,163 @@ +// Copyright 2012 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 rand_test + +import ( + "fmt" + "os" + "strings" + "text/tabwriter" + + "golang.org/x/exp/rand" +) + +// These tests serve as an example but also make sure we don't change +// the output of the random number generator when given a fixed seed. + +func Example() { + rand.Seed(42) // Try changing this number! + answers := []string{ + "It is certain", + "It is decidedly so", + "Without a doubt", + "Yes definitely", + "You may rely on it", + "As I see it yes", + "Most likely", + "Outlook good", + "Yes", + "Signs point to yes", + "Reply hazy try again", + "Ask again later", + "Better not tell you now", + "Cannot predict now", + "Concentrate and ask again", + "Don't count on it", + "My reply is no", + "My sources say no", + "Outlook not so good", + "Very doubtful", + } + fmt.Println("Magic 8-Ball says:", answers[rand.Intn(len(answers))]) + // Output: Magic 8-Ball says: Most likely +} + +// This example shows the use of each of the methods on a *Rand. +// The use of the global functions is the same, without the receiver. +func Example_rand() { + // Create and seed the generator. + // Typically a non-fixed seed should be used, such as time.Now().UnixNano(). + // Using a fixed seed will produce the same output on every run. + r := rand.New(rand.NewSource(1234)) + + // The tabwriter here helps us generate aligned output. + w := tabwriter.NewWriter(os.Stdout, 1, 1, 1, ' ', 0) + defer w.Flush() + show := func(name string, v1, v2, v3 interface{}) { + fmt.Fprintf(w, "%s\t%v\t%v\t%v\n", name, v1, v2, v3) + } + + // Float32 and Float64 values are in [0, 1). + show("Float32", r.Float32(), r.Float32(), r.Float32()) + show("Float64", r.Float64(), r.Float64(), r.Float64()) + + // ExpFloat64 values have an average of 1 but decay exponentially. + show("ExpFloat64", r.ExpFloat64(), r.ExpFloat64(), r.ExpFloat64()) + + // NormFloat64 values have an average of 0 and a standard deviation of 1. + show("NormFloat64", r.NormFloat64(), r.NormFloat64(), r.NormFloat64()) + + // Int31, Int63, and Uint32 generate values of the given width. + // The Int method (not shown) is like either Int31 or Int63 + // depending on the size of 'int'. + show("Int31", r.Int31(), r.Int31(), r.Int31()) + show("Int63", r.Int63(), r.Int63(), r.Int63()) + show("Uint32", r.Uint32(), r.Uint32(), r.Uint32()) + show("Uint64", r.Uint64(), r.Uint64(), r.Uint64()) + + // Intn, Int31n, Int63n and Uint64n limit their output to be < n. + // They do so more carefully than using r.Int()%n. + show("Intn(10)", r.Intn(10), r.Intn(10), r.Intn(10)) + show("Int31n(10)", r.Int31n(10), r.Int31n(10), r.Int31n(10)) + show("Int63n(10)", r.Int63n(10), r.Int63n(10), r.Int63n(10)) + show("Uint64n(10)", r.Uint64n(10), r.Uint64n(10), r.Uint64n(10)) + + // Perm generates a random permutation of the numbers [0, n). + show("Perm", r.Perm(5), r.Perm(5), r.Perm(5)) + // Output: + // Float32 0.030719291 0.47512934 0.031019364 + // Float64 0.6906635660087743 0.9898818576905045 0.2683634639782333 + // ExpFloat64 1.24979080914592 0.3451975160045876 0.5456817760595064 + // NormFloat64 0.879221333732727 -0.01508980368383761 -1.962250558270421 + // Int31 2043816560 1870670250 1334960143 + // Int63 7860766611810691572 1466711535823962239 3836585920276818709 + // Uint32 2051241581 751073909 1353986074 + // Uint64 10802154207635843641 14398820303406316826 11052107950969057042 + // Intn(10) 3 0 1 + // Int31n(10) 3 8 1 + // Int63n(10) 4 6 0 + // Uint64n(10) 2 9 4 + // Perm [1 3 4 0 2] [2 4 0 3 1] [3 2 0 4 1] +} + +func ExampleShuffle() { + words := strings.Fields("ink runs from the corners of my mouth") + rand.Shuffle(len(words), func(i, j int) { + words[i], words[j] = words[j], words[i] + }) + fmt.Println(words) + + // Output: + // [ink corners of from mouth runs the my] +} + +func ExampleShuffle_slicesInUnison() { + numbers := []byte("12345") + letters := []byte("ABCDE") + // Shuffle numbers, swapping corresponding entries in letters at the same time. + rand.Shuffle(len(numbers), func(i, j int) { + numbers[i], numbers[j] = numbers[j], numbers[i] + letters[i], letters[j] = letters[j], letters[i] + }) + for i := range numbers { + fmt.Printf("%c: %c\n", letters[i], numbers[i]) + } + + // Output: + // D: 4 + // A: 1 + // E: 5 + // B: 2 + // C: 3 +} + +func ExampleLockedSource() { + r := rand.New(new(rand.LockedSource)) + r.Seed(42) // Try changing this number! + answers := []string{ + "It is certain", + "It is decidedly so", + "Without a doubt", + "Yes definitely", + "You may rely on it", + "As I see it yes", + "Most likely", + "Outlook good", + "Yes", + "Signs point to yes", + "Reply hazy try again", + "Ask again later", + "Better not tell you now", + "Cannot predict now", + "Concentrate and ask again", + "Don't count on it", + "My reply is no", + "My sources say no", + "Outlook not so good", + "Very doubtful", + } + fmt.Println("Magic 8-Ball says:", answers[r.Intn(len(answers))]) + // Output: Magic 8-Ball says: Most likely +} |