indexOf方法 在一个字符串中查找另一个字符串的次数
程序员文章站
2022-03-08 22:50:22
...
/**
* "In the entire world there's nobody like me.
*Since the beginning of time, there has never been another person like me.
*Nobody has my smile.
*Nobody has my eyes, my nose, my hair, my hands, or my voice."
* 要求:算出my在这段话中出现的次数?
* 我的思路:
* 1.寻找一个字符串短语在一段字符串中出现几次,首先肯定是用str.indexOf("my",start)方法
* 2.indexOf方法的返回值是int,如果找不到就会返回-1
* 3.利用这一点,可以设定一个循环,并定义一个计数器,
* 让计算机从段落的起始,一直找到末尾,如果找到一个就计数器+1,直到indexof返回结果为-1时,
* 停止循环.
* 4.注意:每一次开始找的位置,是不确定的.每一次的新位置,都是上一次找到"短语的位置"+"短语的长度"
*/
public class IndexDemo {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
String str = "In the entire world there's nobody like me. "
+ "\nSince the beginning of time, "
+ "there has never been another person like me."
+ "\nNobody has my smile. \nNobody has my eyes, "
+ "my nose, my hair, my hands, or my voice.";
int count = 0;
System.out.println("请输入需要查找的单词:");
String key = scan.next();
count = serachWord(str,key);
System.out.println("短语my在段落中出现"+count+"次");
}
/**
* 查找某个单词在段落中出现次数的方法
* @param str
* @return
*/
/**
* @param str
* @param key
* @return
*/
public static int serachWord(String str,String key) {
//记录查找次数
int count = 0;
//记录每次查找的下标位置,初始化
int index = 0;
//定义循环,如果index的位置不是-1,就一值查找
while((index = str.indexOf(key,index))!=-1){
//每循环一次就要明确下一次查找的位置
index = index+key.length();
//每查找一次计数器自增
count ++;
}
return count;
}
}
转载于:https://my.oschina.net/zyjcxc/blog/667304