You can do this: Map<K, V> map = …; ListMultimap<V, K> inverse = Multimaps.invertFrom(Multimaps.forMap(map), ArrayListMultimap.<V,K>create()); Do note that pretty much any time you write Map<K, List<V>> or Map<K, Set<V>> or some such, a ListMultimap<K, V> or SetMultimap<K, V> is what you really want.
In statistics, this is called the “mode”. A vanilla Java 8 solution looks like this: Stream.of(1, 3, 4, 3, 4, 3, 2, 3, 3, 3, 3, 3) .collect(Collectors.groupingBy(Function.identity(), Collectors.counting())) .entrySet() .stream() .max(Map.Entry.comparingByValue()) .ifPresent(System.out::println); Which yields: 3=8 jOOλ is a library that supports mode() on streams. The following program: System.out.println( Seq.of(1, 3, 4, 3, 4, 3, … Read more
As of Guava 21, this is possible via Streams.zip(): List<Person> persons = Streams.zip(names.stream(), ages.stream(), Person::new) .collect(Collectors.toList());
Why doesn’t the enhanced for loop just accept an iterator? I want to gather a few of the potential reasons from the various answers as to why the for-each loop doesn’t simply accept an iterator. Convenience: The for-each loop was created partly for convenience for the common operation of performing an action given each element … Read more
You can use the standard Collections#min() for this. Map<String, Double> map = new HashMap<String, Double>(); map.put(“1.1”, 1.1); map.put(“0.1”, 0.1); map.put(“2.1”, 2.1); Double min = Collections.min(map.values()); System.out.println(min); // 0.1 Update: since you need the key as well, well, I don’t see ways in Collections or Google Collections2 API since a Map is not a Collection. The … Read more
Assuming you have Map<String, Collection<String>> map = …; Multimap<String, String> multimap = ArrayListMultimap.create(); Then I believe this is the best you can do for (String key : map.keySet()) { multimap.putAll(key, map.get(key)); } or the more optimal, but harder to read for (Entry<String, Collection<String>> entry : map.entrySet()) { multimap.putAll(entry.getKey(), entry.getValue()); }
Finally, I found a solution for this. It’s simple guys. Add latest guava jar in your project. Note: If you have already old one jar (Please remove that and add it new one). Follow the link : mvnrepository.com/artifact/com.google.guava/guava/29.0-jre
With some IDE there’s a plugin to debug this kind of case. Anyway google-api-client 1.22.0, as you can see, depends on guava-jdk5 17. That version is in conflict with google-out-library.oath2-http that need version of guava > 20 Try to modify your pom.xml like this <dependency> <groupId>com.google.api-client</groupId> <artifactId>google-api-client</artifactId> <version>1.22.0</version> <exclusions> <exclusion> <groupId>com.google.guava</groupId> <artifactId>guava-jdk5</artifactId> </exclusion> </exclusions> </dependency> … Read more
Do it the old-fashioned way, without Guava. (Speaking as a Guava developer.) List<Person> filtered = Lists.newArrayList(); for(Person p : allPersons) { if(acceptedNames.contains(p.getName())) { filtered.add(p); } } You can do this with Guava, but Java isn’t Python, and trying to make it into Python is just going to perpetuate awkward and unreadable code. Guava’s functional utilities … Read more
The null pointer exception is a result of unboxing the result of inverse.get(animal). If inverse doesn’t contain the key animal, it returns null, “of type” Integer. Given that the assignment is to an int reference, Java unboxes the value into an int, resulting in a null pointer exception. You should either check for inverse.containsKey(animal) or … Read more