- Array
- stream
前言
陣列轉stream可以透過Arrays.stream()或是Stream.of()來達成，但在面對物件陣列、基本型別陣列的返回略有不同
物件陣列轉stream
Arrays.stream(T[] array)Returns a sequential Stream with the specified array as its source.
Stream.of(T t)Returns a sequential Stream containing a single element.
public static void main(String[] args) {
//Object array convert to stream
String [] strs = {"Hello","Duke","Java"};
Arrays.stream(strs).map(s->s.toUpperCase()).forEach(System.out::println);//HELLO DUKE JAVA
Stream.of(strs).map(s->s.toLowerCase()).forEach(System.out::println);//hello duke java
}
基本型別陣列轉stream
stream(int[] array) Returns a sequential IntStream with the specified array as its source. |
Stream.of(T t)Returns a sequential Stream containing a single element.
public static void main(String[] args) {
//primitive array convert to stream
int [] nums = {1,2,3,4,5};
Arrays.stream(nums).forEach(System.out::println);//此處返回的是IntStream，可以直接列印
Stream.of(nums).forEach(System.out::println); //此處返回的是Stream<int[]>，無法直接列印數字
Stream.of(nums).flatMapToInt(s->Arrays.stream(s)).forEach(System.out::println);//必須進行加工後才能直接列印
}
Stream.of其他用法
public static void main(String[] args) {
Stream<String> stream1 = Stream.of("Hello","Duke","Java");
Stream<Integer> stream2 =Stream.of(1,2,3,4);
}
Reference