example_wrapper_test.go

Documentation: sort

		 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 Grams int
		13  
		14  func (g Grams) String() string { return fmt.Sprintf("%dg", int(g)) }
		15  
		16  type Organ struct {
		17  	Name	 string
		18  	Weight Grams
		19  }
		20  
		21  type Organs []*Organ
		22  
		23  func (s Organs) Len() int			{ return len(s) }
		24  func (s Organs) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
		25  
		26  // ByName implements sort.Interface by providing Less and using the Len and
		27  // Swap methods of the embedded Organs value.
		28  type ByName struct{ Organs }
		29  
		30  func (s ByName) Less(i, j int) bool { return s.Organs[i].Name < s.Organs[j].Name }
		31  
		32  // ByWeight implements sort.Interface by providing Less and using the Len and
		33  // Swap methods of the embedded Organs value.
		34  type ByWeight struct{ Organs }
		35  
		36  func (s ByWeight) Less(i, j int) bool { return s.Organs[i].Weight < s.Organs[j].Weight }
		37  
		38  func Example_sortWrapper() {
		39  	s := []*Organ{
		40  		{"brain", 1340},
		41  		{"heart", 290},
		42  		{"liver", 1494},
		43  		{"pancreas", 131},
		44  		{"prostate", 62},
		45  		{"spleen", 162},
		46  	}
		47  
		48  	sort.Sort(ByWeight{s})
		49  	fmt.Println("Organs by weight:")
		50  	printOrgans(s)
		51  
		52  	sort.Sort(ByName{s})
		53  	fmt.Println("Organs by name:")
		54  	printOrgans(s)
		55  
		56  	// Output:
		57  	// Organs by weight:
		58  	// prostate (62g)
		59  	// pancreas (131g)
		60  	// spleen	 (162g)
		61  	// heart		(290g)
		62  	// brain		(1340g)
		63  	// liver		(1494g)
		64  	// Organs by name:
		65  	// brain		(1340g)
		66  	// heart		(290g)
		67  	// liver		(1494g)
		68  	// pancreas (131g)
		69  	// prostate (62g)
		70  	// spleen	 (162g)
		71  }
		72  
		73  func printOrgans(s []*Organ) {
		74  	for _, o := range s {
		75  		fmt.Printf("%-8s (%v)\n", o.Name, o.Weight)
		76  	}
		77  }
		78
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