java.lang.String.indexOf(char ch)
方法返回字符ch在指定字符串中第一次出现的下标索引位置
如果字符ch在指定的字符串中找不到,则返回-1
示例:
import java.lang.*; public class StringDemo { public static void main(String[] args) { String str = "This is tanglc‘s cnblog"; // returns the index of character s appear in the first time System.out.println("index of letter ‘s‘ = " + str.indexOf(‘s‘)); // returns -1 as character e is not in the string System.out.println("index of letter ‘e‘ = " + str.indexOf(‘e‘)); } }
运行结果:
index of letter ‘s‘ = 3
index of letter ‘e‘ = -1