Java String subSequence()用法及代码示例

Java.lang.String.subSequence()是Java中的内置函数，该函数返回CharSequence。 CharSequence，它是此序列的子序列。子序列以指定索引处的char值开始，并以(end-1)处的char值结束。返回序列的长度(以字符为单位)为(end-start，因此，如果start == end，则返回一个空序列。

用法:

public CharSequence subSequence(int start, int end) 
参数：
start - This is the index from where the subsequence starts, it is inclusive.
end - This is the index where the subsequence ends, it is exclusive.

返回值：
它返回范围为[start，end)的指定子序列。

错误和异常：
IndexOutOfBoundsException-如果start或end为负，end大于length()或start大于end，则抛出此错误。

程序1:显示Java.lang.String.subSequence()函数的工作方式。

// Java program to demonstrate working 
// of Java.lang.String.subSequence() method 
import java.lang.Math; 
  
class Gfg { 
  
    // driver code 
    public static void main(String args[]) 
    { 
  
        String Str = "Welcome to geeksforgeeks"; 
  
        // prints the subsequence from 0-7, exclusive 7th index 
        System.out.print("Returns:"); 
        System.out.println(Str.subSequence(0, 7)); 
  
        System.out.print("Returns:"); 
        System.out.println(Str.subSequence(10, 24)); 
    } 
}

输出：

Returns:Welcome
Returns: geeksforgeeks

程序2:当索引为负时显示Java.lang.String.subSequence()函数的错误

// Java program to demonstrate error 
// of Java.lang.String.subSequence() method 
import java.lang.Math; 
  
class Gfg { 
  
    // driver code 
    public static void main(String args[]) 
    { 
  
        String Str = "Welcome to geeksforgeeks"; 
  
        // throws an error as index is negative 
        System.out.print("Returns:"); 
        System.out.println(Str.subSequence(-1, 7)); 
    } 
}

输出：

Exception in thread "main" java.lang.StringIndexOutOfBoundsException:
String index out of range:-1
    at java.lang.String.substring(String.java:1960)
    at java.lang.String.subSequence(String.java:2003)
    at Gfg.main(File.java:15)

程序3:当索引超出范围时显示Java.lang.String.subSequence()函数的错误。

// Java program to demonstrate error 
// of Java.lang.String.subSequence() method 
import java.lang.Math; 
  
class Gfg { 
  
    // driver code 
    public static void main(String args[]) 
    { 
  
        String Str = "Welcome to geeksforgeeks"; 
  
        // throws an error as end is out of range 
        System.out.print("Returns:"); 
        System.out.println(Str.subSequence(10, 50)); 
    } 
}

输出：

Exception in thread "main" java.lang.StringIndexOutOfBoundsException:
String index out of range:50
    at java.lang.String.substring(String.java:1963)
    at java.lang.String.subSequence(String.java:2003)
    at Gfg.main(File.java:16)

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注：本文由纯净天空筛选整理自ChetnaAgarwal大神的英文原创作品 Java String subSequence() method with Examples。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。