Question

使用Java编写程序首先删除字符串"helloworld"中第3-5个字符,然后将该字符串的1-3个字符替换为"12"

Answer 1

String s="helloword";
int i=s.indexOf("l");
s=s.substring(0,i)+s.substring(i+2);
System.out.println(s);
s=12+s.substring(3);
System.out.println(s);

Answer 2

String str="helloworld";
String subStr1=str.substring(0,2);
String subStr2=str.substring(5,str.length());
String newStr=subStr1+subStr2;
String subStr3=newStr.substring(3,newStr.length());
String resultStr="12"+subStr3; //最后结果

Answer 3

str = "helloworld";
str.delete(3,5);
str.replace(1,3,"12");
不清楚的看看这个
http://blog.163.com/hn_myj@126/blog/static/50555635200861133942947/