sort: update main example to use Slice along with Sort

This is to let sort.Slice get more prominence since
it's the most common use case.

Fixes #21989

Change-Id: I0b180cc20256f5f09065b722e191c508c872f4f7
Reviewed-on: https://go-review.googlesource.com/65710
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/sort/example_interface_test.go b/src/sort/example_interface_test.go
index 442204ea9eb93949e91df2b5fee7d553c5ce11a4..72d3017a828ae8c40013b99469f00f7c228a9cb9 100644 (file)
--- a/src/sort/example_interface_test.go
+++ b/src/sort/example_interface_test.go
@@ -35,10 +35,24 @@ func Example() {
        }
 
        fmt.Println(people)
+       // There are two ways to sort a slice. First, one can define
+       // a set of methods for the slice type, as with ByAge, and
+       // call sort.Sort. In this first example we use that technique.
        sort.Sort(ByAge(people))
        fmt.Println(people)
 
+       // The other way is to use sort.Slice with a custom Less
+       // function, which can be provided as a closure. In this
+       // case no methods are needed. (And if they exist, they
+       // are ignored.) Here we re-sort in reverse order: compare
+       // the closure with ByAge.Less.
+       sort.Slice(people, func(i, j int) bool {
+               return people[i].Age > people[j].Age
+       })
+       fmt.Println(people)
+
        // Output:
        // [Bob: 31 John: 42 Michael: 17 Jenny: 26]
        // [Michael: 17 Jenny: 26 Bob: 31 John: 42]
+       // [John: 42 Bob: 31 Jenny: 26 Michael: 17]
 }