Java StringBuilder deleteCharAt()用法及代碼示例

StringBuilder類的deleteCharAt(int index)方法從StringBuilder包含的String中刪除給定索引處的字符。此方法將index作為參數，該參數表示我們要刪除的char的索引，並將剩餘的String作為StringBuilder對象返回。應用此方法後，此StringBuilder縮短一個字符。

用法:

public StringBuilder deleteCharAt(int index)

參數：此方法接受一個參數索引，該參數代表要刪除的字符的索引。

返回值：刪除字符後，此方法返回此StringBuilder對象。

異常：如果索引小於零或索引大於String的長度，則此方法將引發StringIndexOutOfBoundsException。

下麵的程序演示StringBuilder類的deleteCharAt()方法：

示例1:

// Java program to demonstrate 
// the deleteCharAt() Method. 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        // create a StringBuilder object 
        // with a String pass as parameter 
        StringBuilder 
            str 
            = new StringBuilder("WelcomeGeeks"); 
  
        // print string 
        System.out.println("Before removal String = "
                           + str.toString()); 
  
        // remove the Character from index 8 
        StringBuilder afterRemoval = str.deleteCharAt(8); 
  
        // print string after removal of Character 
        System.out.println("After removal of character"
                           + " at index 8 = "
                           + afterRemoval.toString()); 
    } 
}

輸出：

Before removal String = WelcomeGeeks
After removal of character at index 8 = WelcomeGeks

示例2:

// Java program to demonstrate 
// the deleteCharAt() Method. 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        // create a StringBuilder object 
        // with a String pass as parameter 
        StringBuilder 
            str 
            = new StringBuilder("GeeksforGeeks"); 
  
        // print string 
        System.out.println("Before removal String = "
                           + str.toString()); 
  
        // remove the Character from index 3 
        str = str.deleteCharAt(3); 
  
        // print string after removal of Character 
        System.out.println("After removal of Character"
                           + " from index=3"
                           + " String becomes => "
                           + str.toString()); 
  
        // remove the substring from index 5 
        str = str.deleteCharAt(5); 
  
        // print string after removal of Character 
        System.out.println("After removal of Character"
                           + " from index=5"
                           + " String becomes => "
                           + str.toString()); 
    } 
}

輸出：

Before removal String = GeeksforGeeks
After removal of Character from index=3 String becomes => GeesforGeeks
After removal of Character from index=5 String becomes => GeesfrGeeks

示例3:刪除IndexOutOfBoundException

// Java program to demonstrate 
// exception thrown by the deleteCharAt() Method. 
  
class GFG { 
    public static void main(String[] args) 
    { 
  
        // create a StringBuilder object 
        // with a String pass as parameter 
        StringBuilder 
            str 
            = new StringBuilder("evil dead_01"); 
  
        try { 
  
            // make index > length of String 
            StringBuilder 
                afterRemoval 
                = str.deleteCharAt(14); 
        } 
  
        catch (Exception e) { 
            System.out.println("Exception: " + e); 
        } 
    } 
}

輸出：

Exception: java.lang.StringIndexOutOfBoundsException: String index out of range: 14

參考：
https://docs.oracle.com/javase/10/docs/api/java/lang/StringBuilder.html#deleteCharAt(int)

相關用法

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