`Collections.replaceAll()` 方法和 `List.replaceAll()` 方法
接口 `Collections` 的 `replaceAll()` 方法接受一个 `List` 对象,两个类型参数表示旧值和新值,将列表中旧值替换为新值。
示例
import java.util.ArrayList; import java.util.Collections; import java.util.List; public class ReplaceAllExample { public static void main(String args[]) { List<String> list = new ArrayList<String>(); list.add("Java"); list.add("Java Script"); list.add("HBase"); list.add("CoffeeScript"); list.add("TypeScript"); System.out.println("Contents of list: "+list); Collections.replaceAll(list, "Java", "JAVA"); System.out.print("Contents of list after replace operation: \n"+list); } }
输出
Contents of list: [Java, Java Script, HBase, CoffeeScript, TypeScript] Contents of list after replace operation: [JAVA, Java Script, HBase, CoffeeScript, TypeScript]
`List` 接口的 `replaceAll()` 方法接受一个表示特定操作的 `UnaryOperator` 对象,对当前列表的所有元素执行指定操作,并将现有值替换为结果值。
示例
import java.util.ArrayList; import java.util.function.UnaryOperator; class Op implements UnaryOperator<String> { public String apply(String str) { return str.toUpperCase(); } } public class Test { public static void main(String[] args) throws CloneNotSupportedException { ArrayList<String> list = new ArrayList<>(); list.add("Java"); list.add("JavaScript"); list.add("CoffeeScript"); list.add("HBase"); list.add("OpenNLP"); System.out.println("Contents of the list: "+list); list.replaceAll(new Op()); System.out.println("Contents of the list after replace operation: \n"+list); } }
输出
Contents of the list: [Java, JavaScript, CoffeeScript, HBase, OpenNLP] Contents of the list after replace operation: [JAVA, JAVASCRIPT, COFFEESCRIPT, HBASE, OPENNLP]
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