📅  最后修改于: 2020-09-26 05:41:56             🧑  作者: Mango
Java 字符串 lastIndexOf()方法返回给定字符值或子字符串的最后一个索引。如果找不到,则返回-1。索引计数器从零开始。
public int lastIndexOf(int ch) {
return lastIndexOf(ch, value.length - 1);
}
Java中有4种类型的lastIndexOf方法。 lastIndexOf方法的签名如下:
No. | Method | Description |
---|---|---|
1 | int lastIndexOf(int ch) | returns last index position for the given char value |
2 | int lastIndexOf(int ch, int fromIndex) | returns last index position for the given char value and from index |
3 | int lastIndexOf(String substring) | returns last index position for the given substring |
4 | int lastIndexOf(String substring, int fromIndex) | returns last index position for the given substring and from index |
ch:char值,即单个字符,例如“ a”
fromIndex:从此处获取char值或子字符串的索引的索引位置
substring:要在此字符串搜索的子字符串
字符串的最后一个索引
public class LastIndexOfExample{
public static void main(String args[]){
String s1=this is index of example;//there are 2 's' characters in this sentence
int index1=s1.lastIndexOf('s');//returns last index of 's' char value
System.out.println(index1);//6
}}
输出:
"6
在这里,我们通过指定fromIndex从字符串中找到最后一个索引
public class LastIndexOfExample2 {
public static void main(String[] args) {
String str = This is index of example;
int index = str.lastIndexOf('s',5);
System.out.println(index);
}
}
输出:
3
它返回子字符串的最后一个索引。
public class LastIndexOfExample3 {
public static void main(String[] args) {
String str = This is last index of example;
int index = str.lastIndexOf(of);
System.out.println(index);
}
}
输出:
19
它从fromIndex返回子字符串的最后一个索引。
public class LastIndexOfExample4 {
public static void main(String[] args) {
String str = This is last index of example;
int index = str.lastIndexOf(of, 25);
System.out.println(index);
index = str.lastIndexOf(of, 10);
System.out.println(index); // -1, if not found
}
}
输出:
19
-1