接受界面中的一片与结构B的切片呼叫转到功能（B实现A）

• Z时代
• 2024-01-10
• 分类：问答

我有以下几种类型：接受界面中的一片与结构B的切片呼叫转到功能（B实现A）

type Statement interface { 
    Say() string 
} 
type Quote struct { 
    quote string 
} 
func (p Quote) Say() string { 
    return p.quote 
} 
func Replay(conversation []Statement) { 
    for _, statement := range conversation { 
     fmt.Println(statement.Say()) 
    } 
} 

我想我为什么功能的一个相当不错的把握接受[]Statement类型的参数，不能用[]Quote调用;即使Quote实施了Statement,[]Quote也没有实施[]Statement。 []Statement甚至不是一个接口。它有slice of Statement。虽然Go隐式地从类型转换为接口类型，但它不会从A类型的片段到片段接口B的隐式转换。

我们可以将报价转换为明确声明：

conversation := []Quote{ 
    Quote{"Nice Guy Eddie: C'mon, throw in a buck!"}, 
    Quote{"Mr. Pink: Uh-uh, I don't tip."}, 
    Quote{"Nice Guy Eddie: You don't tip?"}, 
    Quote{"Mr. Pink: Nah, I don't believe in it."}, 
    Quote{"Nice Guy Eddie: You don't believe in tipping?"}, 
} 
// This doesn't work 
// Replay(conversation) 
// Create statements from quotes 
statements := make([]Statement, len(conversation)) 
for i, quote := range conversation { 
    statements[i] = quote 
} 
Replay(statements) 

现在说，重播是要出门其方式是多么容易使用重播库的一部分。只要这些对象实现了Statement接口，它就允许您使用任何切片对象调用Replay。要做到这一点，有以下转换方法：

func ConvertToStatements(its interface{}) ([]Statement, error) { 
    itsValue := reflect.ValueOf(its) 
    itsKind := itsValue.Kind() 
    if itsKind != reflect.Array && itsKind != reflect.Slice { 
     return nil, fmt.Errorf("Expected items to be an Array or a Slice, got %s", itsKind) 
    } 
    itsLength := itsValue.Len() 
    items := make([]Statement, itsLength) 
    for i := 0; i < itsLength; i++ { 
     itsItem := itsValue.Index(i) 
     if item, ok := itsItem.Interface().(Statement); ok { 
      items[i] = item 
     } else { 
      return nil, fmt.Errorf("item #%d does not implement the Statement interface: %s", i, itsItem) 
     } 
    } 
    return items, nil 
} 

重播看起来是这样的：

func Replay(its interface{}) { 
    conversation := ConvertToStatements(its) 
    for _, statement := range conversation { 
     fmt.Println(statement.Say()) 
    } 
} 

现在，我们可以直接调用重播时报价：

Replay(conversation) 

最后，我的问题：只要A实现Statement接口，是否有更简单的方法允许Replay接受任何类型A的切片？

回答：

回答：

回答：

package main 
import "fmt" 
type Statement interface { 
    Say() string 
} 
type Statements []Statement 
type Quote struct { 
    quote string 
} 
type Quotes []Quote 
func (p Quote) Say() string { 
    return p.quote 
} 
type Attributed struct { 
    who string 
    quote string 
} 
func (p Attributed) Say() string { 
    return p.who + ": " + p.quote 
} 
func Replay(conversation []Statement) { 
    for _, s := range conversation { 
     fmt.Println(s.Say()) 
    } 
} 
func (q Quotes) toStatements() Statements { 
    conv := make(Statements, len(q)) 
    for i, v := range q { 
     conv[i] = Statement(v) 
    } 
    return conv 
} 
func main() { 
    conversation := Statements{ 
     Quote{"Nice Guy Eddie: C'mon, throw in a buck!"}, 
     Quote{"Mr. Pink: Uh-uh, I don't tip."}, 
     Attributed{"Nice Guy Eddie", "You don't tip?"}, // <= another type 
     Quote{"Mr. Pink: Nah, I don't believe in it."}, 
     Quote{"Nice Guy Eddie: You don't believe in tipping?"}, 
    } 
    myquotes := Quotes{ 
     Quote{"Nice Guy Eddie: C'mon, throw in a buck!"}, 
     Quote{"Mr. Pink: Uh-uh, I don't tip."}, 
     Quote{"Nice Guy Eddie: You don't tip?"}, 
     Quote{"Mr. Pink: Nah, I don't believe in it."}, 
     Quote{"Nice Guy Eddie: You don't believe in tipping?"}, 
    } 
    Replay(conversation) 
    Replay(myquotes.toStatements()) 
} 

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