Java 中的 MatchResult start(int)方法，示例
原文:https://www . geesforgeks . org/match result-startint-method-in-Java-with-examples/
匹配结果界面的开始(int group) 方法用于从指定的组中获取已经完成的匹配结果的开始索引。
语法:
public int start(int group)
参数:该方法取一个参数组，该组是需要匹配模式的起始索引的组。
返回值:该方法返回指定组中第一个匹配字符的索引。
异常:如果还没有尝试匹配，或者之前的匹配操作失败，这个方法抛出:
- 【非法状态】 。
- Index out of bounds exception If there is no capture group in the pattern of the given index.
下面的例子说明了 MatchResult.start()方法:
例 1:
// Java code to illustrate start() method
import java.util.regex.*;
public class GFG {
public static void main(String[] args)
{
// Get the regex to be checked
String regex = "(G*s)";
// 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
MatchResult matcher
= pattern
.matcher(stringToBeMatched);
while (((Matcher)matcher).find()) {
// Get the first index of match result
System.out.println(matcher.start(1));
}
}
}
输出:
4
12
例 2:
// Java code to illustrate start() method
import java.util.regex.*;
public class GFG {
public static void main(String[] args)
{
// Get the regex to be checked
String regex = "(G*G)";
// 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
MatchResult matcher
= pattern
.matcher(stringToBeMatched);
while (((Matcher)matcher).find()) {
// Get the first index of match result
System.out.println(matcher.start(0));
}
}
}
输出:
0
2
4
6
8
10
12
14
16
18
=
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