Question

我有以下MultiMap：

Multimap<String, Integer> mm = ArrayListMultimap.create();

mm.put("A", 10);
mm.put("B", 0);
mm.put("C", 0);
mm.put("A", 0);
mm.put("B", 11);
mm.put("C", 0);         
mm.put("A", 0);
mm.put("B", 0);             
mm.put("C", 5);     
mm.put("A", 4);
mm.put("B", 0);
mm.put("C", 0);     
mm.put("A", 0);
mm.put("B", 6);
mm.put("C", 0);     
mm.put("A", 0);
mm.put("B", 0);             
mm.put("C", 8);     
mm.put("A", 2);
mm.put("B", 0);
mm.put("C", 0);     
mm.put("A", 0);
mm.put("B", 0);
mm.put("C", 0);     
mm.put("A", 0);
mm.put("B", 0);             
mm.put("C", 7);

Set<String> keys = mm.keySet();
for (String key : keys) {           
    System.out.println("Key = " + key);
        System.out.println("Values = " + mm.get(key));          
}

我得到以下输出：

Key = A
  值= [10,0,0,4,0,0,2,0,0]
  键= B
  值= [0,11,0,0,6,0,0,0,0]
  键= C
  值= [0,0,5,0,0,0,0,0,7]

但我需要格式为

的输出

Key = A
  值= [10,4,2]
  键= B
  值= [11,6,0]
  键= C
  值= [5,8,7]

Answer 1

您应该使用Multimap<String, Integer> mm = HashMultimap.create();代替HashMultimap

if(!mm.containsValue(10)){
    mm.put("A", 10);
}

或者如果{{1}}对您来说不够，您可以在将值放入多图之前检查该值。

{{1}}

Answer 2

使用Multiset而非Multimap可以更轻松地解决您的使用案例。首先编写一个辅助方法：

static <T> void  addNTimes(Multiset<T> multiset, T item, int n) {
    multiset.addAll(Collections.nCopies(item, n));
}

现在您可以重写代码：

Multiset<String> mm = HashMultiset.create();

addNTimes(mm, "A", 10);
addNTimes(mm, "B", 0);
addNTimes(mm, "C", 0);
addNTimes(mm, "A", 0);
addNTimes(mm, "B", 11);
addNTimes(mm, "C", 0);


Set<Entry<String>> keys = mm.entrySet();
for (Entry<String> entry : keys) {
    System.out.println("Key = " + entry.getElement());
    System.out.println("Values = " + entry.getCount());
}

java guava multimap输出特定格式

2 个答案: