java 正则表达式 表示字符串首字母

Posted 2023-03-03

各位大虾，请问在java中用正则表达式 表示字符串首字母改怎么表示。比如我想把
what do you do?这句话的首字母都变成大写，用正则表达式怎么表示？

正则只是匹配，可以匹配到你要找的串， 之后对匹配的串的处理，是需要java程序自己做的。追问

那我该怎么匹配呢？

追答

你要的是这种效果吗:What Do You Do?
String a ="what do you do?";
String[] b =a.split("\\s+");
StringBuffer sb =new StringBuffer();
for (int i=0;i<b.length;i++)
sb.append(String.valueOf(b[i].charAt(0)).toUpperCase()+b[i].substring(1)+" ");

System.out.println(sb);

参考技术A package com.marslei.test;

import java.io.UnsupportedEncodingException;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class marslei_com
public static void main(String[] args) throws UnsupportedEncodingException
String regex="^\\w";
Pattern pattern=Pattern.compile(regex);
String raw="hello, i am marslei.";
System.out.println(raw);
Matcher matcher=pattern.matcher(raw);
String firstChar="";
if(matcher.find())

firstChar=matcher.group();
System.out.println("firstChar="+firstChar);

raw=raw.replaceFirst(regex, firstChar.toUpperCase());
System.out.println(raw);


参考技术B import java.util.regex.*;
class Test

public static void main(String[] args) throws Exception

String str="what do you do?skdfiewhat do you do?lskjfwhat do you do?lksdfiewhat do you do?";
Pattern pattern=Pattern.compile("what do you do");
Matcher matcher=pattern.matcher(str);
String temp=matcher.replaceAll("What do you do");
System.out.println(temp);