github.com/zebozhuang/go@v0.0.0-20200207033046-f8a98f6f5c5d/src/sort/example_interface_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 sort_test
     6  
     7  import (
     8  	"fmt"
     9  	"sort"
    10  )
    11  
    12  type Person struct {
    13  	Name string
    14  	Age  int
    15  }
    16  
    17  func (p Person) String() string {
    18  	return fmt.Sprintf("%s: %d", p.Name, p.Age)
    19  }
    20  
    21  // ByAge implements sort.Interface for []Person based on
    22  // the Age field.
    23  type ByAge []Person
    24  
    25  func (a ByAge) Len() int           { return len(a) }
    26  func (a ByAge) Swap(i, j int)      { a[i], a[j] = a[j], a[i] }
    27  func (a ByAge) Less(i, j int) bool { return a[i].Age < a[j].Age }
    28  
    29  func Example() {
    30  	people := []Person{
    31  		{"Bob", 31},
    32  		{"John", 42},
    33  		{"Michael", 17},
    34  		{"Jenny", 26},
    35  	}
    36  
    37  	fmt.Println(people)
    38  	sort.Sort(ByAge(people))
    39  	fmt.Println(people)
    40  
    41  	// Output:
    42  	// [Bob: 31 John: 42 Michael: 17 Jenny: 26]
    43  	// [Michael: 17 Jenny: 26 Bob: 31 John: 42]
    44  }