libgo/go/sort/example_search_test.go

   1 // Copyright 2016 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 sort_test
   6
   7 import (
   8         "fmt"
   9         "sort"
  10 )
  11
  12 // This example demonstrates searching a list sorted in ascending order.
  13 func ExampleSearch() {
  14         a := []int{1, 3, 6, 10, 15, 21, 28, 36, 45, 55}
  15         x := 6
  16
  17         i := sort.Search(len(a), func(i int) bool { return a[i] >= x })
  18         if i < len(a) && a[i] == x {
  19                 fmt.Printf("found %d at index %d in %v\n", x, i, a)
  20         } else {
  21                 fmt.Printf("%d not found in %v\n", x, a)
  22         }
  23         // Output:
  24         // found 6 at index 2 in [1 3 6 10 15 21 28 36 45 55]
  25 }
  26
  27 // This example demonstrates searching a list sorted in descending order.
  28 // The approach is the same as searching a list in ascending order,
  29 // but with the condition inverted.
  30 func ExampleSearch_descendingOrder() {
  31         a := []int{55, 45, 36, 28, 21, 15, 10, 6, 3, 1}
  32         x := 6
  33
  34         i := sort.Search(len(a), func(i int) bool { return a[i] <= x })
  35         if i < len(a) && a[i] == x {
  36                 fmt.Printf("found %d at index %d in %v\n", x, i, a)
  37         } else {
  38                 fmt.Printf("%d not found in %v\n", x, a)
  39         }
  40         // Output:
  41         // found 6 at index 7 in [55 45 36 28 21 15 10 6 3 1]
  42 }
  43
  44 // This example demonstrates searching for float64 in a list sorted in ascending order.
  45 func ExampleSearchFloat64s() {
  46         a := []float64{1.0, 2.0, 3.3, 4.6, 6.1, 7.2, 8.0}
  47
  48         x := 2.0
  49         i := sort.SearchFloat64s(a, x)
  50         fmt.Printf("found %g at index %d in %v\n", x, i, a)
  51
  52         x = 0.5
  53         i = sort.SearchFloat64s(a, x)
  54         fmt.Printf("%g not found, can be inserted at index %d in %v\n", x, i, a)
  55         // Output:
  56         // found 2 at index 1 in [1 2 3.3 4.6 6.1 7.2 8]
  57         // 0.5 not found, can be inserted at index 0 in [1 2 3.3 4.6 6.1 7.2 8]
  58 }
  59
  60 // This example demonstrates searching for int in a list sorted in ascending order.
  61 func ExampleSearchInts() {
  62         a := []int{1, 2, 3, 4, 6, 7, 8}
  63
  64         x := 2
  65         i := sort.SearchInts(a, x)
  66         fmt.Printf("found %d at index %d in %v\n", x, i, a)
  67
  68         x = 5
  69         i = sort.SearchInts(a, x)
  70         fmt.Printf("%d not found, can be inserted at index %d in %v\n", x, i, a)
  71         // Output:
  72         // found 2 at index 1 in [1 2 3 4 6 7 8]
  73         // 5 not found, can be inserted at index 4 in [1 2 3 4 6 7 8]
  74 }