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Copy pathFiltering.java
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54 lines (43 loc) · 1.53 KB
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package com.brianway.learning.java8.streamapi.usage;
import com.brianway.learning.java8.streamapi.Dish;
import static com.brianway.learning.java8.streamapi.Dish.menu;
import static java.util.stream.Collectors.toList;
import java.util.Arrays;
import java.util.List;
/**
* 筛选
* - 谓词筛选：filter
* - 筛选互异的元素：distinct
* - 忽略头几个元素：limit
* - 截短至指定长度：skip
*/
public class Filtering {
public static void main(String... args) {
// Filtering with predicate
List<Dish> vegetarianMenu =
menu.stream()
.filter(Dish::isVegetarian)
.collect(toList());
vegetarianMenu.forEach(System.out::println);
// Filtering unique elements
List<Integer> numbers = Arrays.asList(1, 2, 1, 3, 3, 2, 4);
numbers.stream()
.filter(i -> i % 2 == 0)
.distinct()
.forEach(System.out::println);
// Truncating a stream
List<Dish> dishesLimit3 =
menu.stream()
.filter(d -> d.getCalories() > 300)
.limit(3)
.collect(toList());
dishesLimit3.forEach(System.out::println);
// Skipping elements
List<Dish> dishesSkip2 =
menu.stream()
.filter(d -> d.getCalories() > 300)
.skip(2)
.collect(toList());
dishesSkip2.forEach(System.out::println);
}
}