Java Collections replaceAll()
Java Collections 类的
replaceAll()方法用于替换列表中一个指定值的所有出现。
语法
以下是
replaceAll()方法的声明:
public static <T> boolean replaceAll(List<T> list, T oldVal, T newVal)
参数
| 参数 |
说明 |
必需/可选 |
| list |
这是要进行替换的列表。 |
必需 |
| oldVal |
这是将要替换的旧值。 |
必需 |
| newVal |
这是要替换oldVal的新值。 |
必需 |
返回
如果列表包含一个或多个元素，例如(oldVal == null，则
replaceAll()方法返回true ？e == null: oldVal.equals(e)。)
异常
UnsupportedOperationException -如果指定了该异常，则抛出此异常列表或其列表迭代器不支持set操作。
兼容版本
Java 1.4及更高版本
示例1
import java.util.*;
public class CollectionsReplaceAllExample1 {
public static void main(String[] args) {
//Create vector and add element in this vector
Vector<String> vector = new Vector<String>();
vector.add("Java");
vector.add("SSSIT");
vector.add("HINDI100");
vector.add("Java");
System.out.println("Initial values are :"+vector);
//Replace 'Java' with 'JavaTpont'
Collections.replaceAll(vector, "Java", "JavaTpont");
System.out.println("Value after replace :"+ vector);
}
}
输出:
Initial values are :[Java, SSSIT, HINDI100, Java]
Value after replace :[JavaTpont, SSSIT, HINDI100, JavaTpont]
示例2
import java.util.*;
public class CollectionsReplaceAllExample2 {
public static void main(String[] args) {
//Create an list of String
List<String> list = Arrays.asList("one", "two", "one");
System.out.println("Original List:- "+list);
boolean b = Collections.replaceAll(list, "one", "three");
System.out.println("Boolean: "+b);
System.out.println("Value after replace:- "+list);
}
}
输出:
Original List:- [one, two, one]
Boolean: true
Value after replace:- [three, two, three]
示例3
import java.util.*;
public class CollectionsReplaceAllExample3 {
public static void main(String[] args) {
//Create an list of integers
List<String> list = Arrays.asList("10", "20", "10", "40", "50", "10");
System.out.println("Original List: " +list);
boolean b = Collections.replaceAll(list, "10", "400");
System.out.println("Boolean: "+b);
System.out.println("Value after Replace: " +list);
}
}
输出:
Original List: [10, 20, 10, 40, 50, 10]
Boolean: true
Value after Replace: [400, 20, 400, 40, 50, 400]
