删除那些属性不在 commons-collections 集合中的属性

发布于 2024-12-17 03:42:35 字数 704 浏览 2 评论 0原文

假设我有一个 foodGroupIds 集合和一个 food 集合。使用commons-collections，如何过滤掉不属于任何食物组的食物？

我可能走在正确的轨道上，但无法弄清楚要使用什么谓词。也许必须创建我自己的？

Collection<Long> ids = collect(
    findGoodFoodGroups(),
    invokerTransformer("getId"));

Collection<Food> food = getAllFood();
filter(food, transformedPredicate(
    invokerTransformer("getFoodGroupId"),
    ?));

在 C# 中，这将是这样的：

var ids = FindGoodFoodGroups().Select(x => x.Id);
var goodFood = FindAllFood().Select(x => ids.Contains(x.FoodGroupId));

我希望所有类型 T 的属性 P 等于集合中的任何 T 的对象>C 具有 T 类型的对象。

原文

Say I have a collection of foodGroupIds and a collection of food. Using commons-collections, how can I filter out the food which does not belong to any of the food groups?

I might be on the right track, but can't figure out what predicate to use. Maybe have to create my own?

Collection<Long> ids = collect(
    findGoodFoodGroups(),
    invokerTransformer("getId"));

Collection<Food> food = getAllFood();
filter(food, transformedPredicate(
    invokerTransformer("getFoodGroupId"),
    ?));

In C# this would be something like this:

var ids = FindGoodFoodGroups().Select(x => x.Id);
var goodFood = FindAllFood().Select(x => ids.Contains(x.FoodGroupId));

I want all objects whose property P of type T is equal to any T in a collection C with objects of type T.

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瑶笙 2024-12-24 03:42:35

我认为你可以使用集合.removeAll(集合)。

简单的例子：

    Map food = new HashMap();
    food.put("appleKey", "apple");
    food.put("orangeKey", "orange");
    food.put("tomatoKey", "tomato");

    Set unmatchedKeys = new HashSet(food.keySet());
    unmatchedKeys.removeAll(Arrays.asList("orangeKey"));
    System.err.println(unmatchedKeys);

    Collection unmatchedValues = new ArrayList(food.values());
    unmatchedValues.removeAll(Arrays.asList("apple", "tomato"));
    System.err.println(unmatchedValues);

输出是：

[appleKey, tomatoKey]
[orange]

I think you could use Collection.removeAll(Collection).

Simple examples:

    Map food = new HashMap();
    food.put("appleKey", "apple");
    food.put("orangeKey", "orange");
    food.put("tomatoKey", "tomato");

    Set unmatchedKeys = new HashSet(food.keySet());
    unmatchedKeys.removeAll(Arrays.asList("orangeKey"));
    System.err.println(unmatchedKeys);

    Collection unmatchedValues = new ArrayList(food.values());
    unmatchedValues.removeAll(Arrays.asList("apple", "tomato"));
    System.err.println(unmatchedValues);

Output is: