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  }
    75
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