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  1. // Playground for https://stackoverflow.com/a/56699658/11458991
  2.  
  3. package main
  4.  
  5. import (
  6. 	"fmt"
  7. 	"errors"
  8. 	"log"
  9. 	"reflect"
  10. 	"strings"
  11. )
  12.  
  13. // RowID stores the ID of a single row in a table. An ID can be a composite of multiple columns
  14. type RowID []string
  15.  
  16. // String implements Stringer interface for RowID
  17. func (r RowID) String() string {
  18. 	return fmt.Sprintf("[%s]", strings.Join(r, ", "))
  19. }
  20.  
  21. func castToStringerSlice(iface interface{}) ([]fmt.Stringer, bool /* ok */) {
  22. 	if reflect.TypeOf(iface).Kind() != reflect.Slice {
  23. 		return nil, false
  24. 	}
  25.  
  26.     v := reflect.ValueOf(iface)
  27. 	stringers := make([]fmt.Stringer, v.Len())
  28.  
  29.     for i := 0; i < v.Len(); i++ {
  30.         stringers[i] = v.Index(i)
  31.     }
  32.  
  33.     return stringers, true
  34. }
  35.  
  36. func PrintChanges(iface_ids interface{}) {
  37. 	ids, ok := castToStringerSlice(iface_ids)
  38. 	if !ok {
  39. 		log.Fatal(errors.New("the argument to PrintChanges must be a slice of Stringers"))
  40. 	}
  41. 	for _, id := range ids {
  42. 		fmt.Println(id)
  43. 	}
  44. }
  45.  
  46. func PrintChange(id fmt.Stringer) {
  47. 	fmt.Println(id)
  48. }
  49.  
  50. func main() {
  51. 	rowIDs := []RowID{
  52. 		{"1", "2"},
  53. 		{"22"},
  54. 	}
  55.  
  56. 	PrintChange(rowIDs[0])
  57.  
  58. 	PrintChanges(rowIDs)
  59. }
Success #stdin #stdout 0s 3144KB
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[1, 2]
[1 2]
[22]
https://ideone.com/vlrBP9
language:
Go (go 1.12.1)
created:
6 years ago
visibility:
public

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