Java Matcher groupCount()用法及代碼示例

Matcher Class的groupCount()方法用於獲取此Matcher模式中的捕獲組數。

用法:

public int groupCount()

參數：此方法不帶任何參數。

返回值：此方法返回此匹配器模式中的捕獲組數。

下麵的示例說明Matcher.groupCount()方法：

示例1:

// Java code to illustrate groupCount() method 
  
import java.util.regex.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Get the regex to be checked 
        String regex = "Geeks"; 
  
        // Create a pattern from regex 
        Pattern pattern 
            = Pattern.compile(regex); 
  
        // Get the String to be matched 
        String stringToBeMatched 
            = "GeeksForGeeks"; 
  
        // Create a matcher for the input String 
        Matcher matcher 
            = pattern 
                  .matcher(stringToBeMatched); 
  
        // Get the number of capturing groups 
        // using groupCount() method 
        System.out.println(matcher.groupCount()); 
    } 
}

輸出：

示例2:

// Java code to illustrate groupCount() method 
  
import java.util.regex.*; 
  
public class GFG { 
    public static void main(String[] args) 
    { 
  
        // Get the regex to be checked 
        String regex = "GFG"; 
  
        // Create a pattern from regex 
        Pattern pattern 
            = Pattern.compile(regex); 
  
        // Get the String to be matched 
        String stringToBeMatched 
            = "GFGFGFGFGFGFGFGFGFG"; 
  
        // Create a matcher for the input String 
        Matcher matcher 
            = pattern 
                  .matcher(stringToBeMatched); 
  
        // Get the number of capturing groups 
        // using groupCount() method 
        System.out.println(matcher.groupCount()); 
    } 
}

輸出：

參考： Oracle Doc

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