下面是一个完整的示例代码,演示了如何使用Java 8的Stream和Lambda表达式遍历Map: importjava.util.HashMap;importjava.util.Map;publicclassMapExample{publicstaticvoidmain(String[]args){Map<String,Integer>map=newHashMap<>();map.put("A",1);map.put("B",2);map.put("C",3);// 遍历Mapmap.forEach(...
1.2 In above example, we should use flatMap() to convert Stream<String[]> to Stream<String>. TestExample1.java package com.mkyong.java8; import java.util.Arrays; import java.util.stream.Stream; public class TestExample1 { public static void main(String[] args) { String[][] data = ne...
2. show all pairs of two arrays In order to show all possible pairs we need handle every item of numbers2 in the stream of number1. There are multiple stream when invokenumber2.stream()method. So we needflatMapto handle multiple stream and put the result in a new stream. List<Integer...
Examples com.logicbig.example.intstream; importjava.util.stream.IntStream; publicclassMapExample{ publicstaticvoidmain(String...args){ IntStreamintStream=IntStream.range(1,5); IntStreamintStream1=intStream.map(i->i*2); intStream1.forEach(System.out::println); } } Output 2 4 6 8...
This example will produce the following output: Original vertices: [(1, 2), (3, 4), (5, 6), (7, 8)] Scaled vertices: [(2, 4), (6, 8), (10, 12), (14, 16)] Conclusion In this article, we explained what streams are in Java. We mentioned some of the basic methods used...
8. Flatten a NestedHashMap One alternative to a nestedHashMapis to use combined keys. A combined key usually concatenates the two keys from the nested structure with a dot in between. For example, the combined key would beDonut.1,Donut.2, and so on. We can “flatten,” i.e., conver...
Example 1: Map from streams having unique keys Let’s stream the List and collect it to a Map usingCollectors.toMap(keyMapper, valueMapper). We usedid as keyandname as valuein the collector. The generated map has all the unique keys but value may contain duplicates, which is perfectly fin...
Many methods in Collections Framework interfaces are defined in terms of theequalsmethod. For example, the specification for thecontainsKey(Object key)method says: "returnstrueif and only if this map contains a mapping for a keyksuch that(key==null ? k==null : key.equals(k))." This speci...
问Java8:将EnumMap<ExampleEnum、String>转换为Map<String、Object>ENMap<String,Object>newMap=map....
Examples com.logicbig.example.intstream; importjava.util.stream.IntStream; importjava.util.stream.LongStream; publicclassMapToLongExample{ publicstaticvoidmain(String...args){ IntStreamintStream=IntStream.range(1,5); LongStreammapToLong=intStream.mapToLong(i->(long)i+Integer.MAX_VALUE); ...