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How to get n first values from an Iterator in Java 8?
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I have sorted a HashMap using Sort a Map<Key, Value> by values (Java) to that I have a LinkedHashMap, i.e. an Iterable which garantees iteration order.
Now, I'd like to retrieve a java.util.List of the first n entries of the map with a one-liner, if possible with a Java 8 Collection Stream API-technique.
I found how can i get two consecutive values from Iterator which explains that there's a possibility to do that with an array, but that's not elegant, differs from my intention to get a List (although that can be transformed, but it's an unnecessary step) and requires an extra method.
java java-8 java-stream
asked May 23 '17 at 13:03
Karl Richter
2,380112957
add a comment |
up vote
4
down vote
favorite
I have sorted a HashMap using Sort a Map<Key, Value> by values (Java) to that I have a LinkedHashMap, i.e. an Iterable which garantees iteration order.
Now, I'd like to retrieve a java.util.List of the first n entries of the map with a one-liner, if possible with a Java 8 Collection Stream API-technique.
I found how can i get two consecutive values from Iterator which explains that there's a possibility to do that with an array, but that's not elegant, differs from my intention to get a List (although that can be transformed, but it's an unnecessary step) and requires an extra method.
java java-8 java-stream
asked May 23 '17 at 13:03
Karl Richter
2,380112957
add a comment |
up vote
4
down vote
favorite
up vote
4
down vote
favorite
I have sorted a HashMap using Sort a Map<Key, Value> by values (Java) to that I have a LinkedHashMap, i.e. an Iterable which garantees iteration order.
Now, I'd like to retrieve a java.util.List of the first n entries of the map with a one-liner, if possible with a Java 8 Collection Stream API-technique.
I found how can i get two consecutive values from Iterator which explains that there's a possibility to do that with an array, but that's not elegant, differs from my intention to get a List (although that can be transformed, but it's an unnecessary step) and requires an extra method.
java java-8 java-stream
asked May 23 '17 at 13:03
Karl Richter
2,380112957
I have sorted a HashMap using Sort a Map<Key, Value> by values (Java) to that I have a LinkedHashMap, i.e. an Iterable which garantees iteration order.
Now, I'd like to retrieve a java.util.List of the first n entries of the map with a one-liner, if possible with a Java 8 Collection Stream API-technique.
I found how can i get two consecutive values from Iterator which explains that there's a possibility to do that with an array, but that's not elegant, differs from my intention to get a List (although that can be transformed, but it's an unnecessary step) and requires an extra method.
java java-8 java-stream
java java-8 java-stream
asked May 23 '17 at 13:03
Karl Richter
2,380112957
asked May 23 '17 at 13:03
Karl Richter
2,380112957
asked May 23 '17 at 13:03
Karl Richter
2,380112957
asked May 23 '17 at 13:03
Karl Richter
2,380112957
asked May 23 '17 at 13:03
Karl Richter
2,380112957
2,380112957
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
up vote
11
down vote
accepted
Stream the entrySet and limit the Stream to the first n elements:
List<Map.Entry<Key,Value>> firstN =
map.entrySet().stream().limit(n).collect(Collectors.toList());
answered May 23 '17 at 13:05
Eran
272k35431514
add a comment |
up vote
1
down vote
Writing more concise code with StreamEx:
List<Map.Entry<Key,Value>> firstN = EntryStream.of(map).limit(n).toList();
answered May 24 '17 at 18:37
user_3380739
83868
add a comment |
2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
11
down vote
accepted
Stream the entrySet and limit the Stream to the first n elements:
List<Map.Entry<Key,Value>> firstN =
map.entrySet().stream().limit(n).collect(Collectors.toList());
answered May 23 '17 at 13:05
Eran
272k35431514
add a comment |
up vote
11
down vote
accepted
Stream the entrySet and limit the Stream to the first n elements:
List<Map.Entry<Key,Value>> firstN =
map.entrySet().stream().limit(n).collect(Collectors.toList());
answered May 23 '17 at 13:05
Eran
272k35431514
add a comment |
up vote
11
down vote
accepted
up vote
11
down vote
accepted
Stream the entrySet and limit the Stream to the first n elements:
List<Map.Entry<Key,Value>> firstN =
map.entrySet().stream().limit(n).collect(Collectors.toList());
answered May 23 '17 at 13:05
Eran
272k35431514
Stream the entrySet and limit the Stream to the first n elements:
List<Map.Entry<Key,Value>> firstN =
map.entrySet().stream().limit(n).collect(Collectors.toList());
answered May 23 '17 at 13:05
Eran
272k35431514
answered May 23 '17 at 13:05
Eran
272k35431514
answered May 23 '17 at 13:05
Eran
272k35431514
answered May 23 '17 at 13:05
Eran
272k35431514
272k35431514
add a comment |
add a comment |
up vote
1
down vote
Writing more concise code with StreamEx:
List<Map.Entry<Key,Value>> firstN = EntryStream.of(map).limit(n).toList();
answered May 24 '17 at 18:37
user_3380739
83868
add a comment |
up vote
1
down vote
Writing more concise code with StreamEx:
List<Map.Entry<Key,Value>> firstN = EntryStream.of(map).limit(n).toList();
answered May 24 '17 at 18:37
user_3380739
83868
add a comment |
up vote
1
down vote
up vote
1
down vote
Writing more concise code with StreamEx:
List<Map.Entry<Key,Value>> firstN = EntryStream.of(map).limit(n).toList();
answered May 24 '17 at 18:37
user_3380739
83868
Writing more concise code with StreamEx:
List<Map.Entry<Key,Value>> firstN = EntryStream.of(map).limit(n).toList();
answered May 24 '17 at 18:37
user_3380739
83868
answered May 24 '17 at 18:37
user_3380739
83868
answered May 24 '17 at 18:37
user_3380739
83868
answered May 24 '17 at 18:37
user_3380739
83868
83868
add a comment |
add a comment |
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