I'm trying to sort the tableProbability
map into a new one called sorted
. In tableProbability
the values are the following:
Key | Value |
---|---|
M | 0.1 |
U | 0.3 |
L | 0.3 |
T | 0.2 |
I | 0.1 |
I have the following code that sorts the Map
:
LinkedHashMap<Character, Double> sorted = new LinkedHashMap<>();
tableProbability.entrySet()
.stream()
.sorted(Map.Entry.comparingByValue(Comparator.reverseOrder()))
.forEachOrdered(x -> sorted.put(x.getKey(), x.getValue()));
But what I end up getting is the following Map
:
Key | Value |
---|---|
L | 0.3 |
U | 0.3 |
T | 0.2 |
I | 0.1 |
M | 0.1 |
And what I am supposed to get is:
Key | Value |
---|---|
U | 0.3 |
L | 0.3 |
T | 0.2 |
M | 0.1 |
I | 0.1 |
Is there any way to retain the duplicate order or at least when it finds a duplicate to put it past the one with the equal value?
Your code works fine, but you can simplify it as follows:
Source map:
LinkedHashMap<Character, Double> tableProbability = new LinkedHashMap<>() {{ put('M', 0.1); put('U', 0.3); put('L', 0.3); put('T', 0.2); put('I', 0.1); }};
System.out.println(tableProbability); // {M=0.1, U=0.3, L=0.3, T=0.2, I=0.1}
This code works fine:
LinkedHashMap<Character, Double> sorted = new LinkedHashMap<>(); tableProbability.entrySet().stream().sorted(Map.Entry.comparingByValue(Comparator.reverseOrder())).forEachOrdered(x -> sorted.put(x.getKey(), x.getValue()));
System.out.println(sorted); // {U=0.3, L=0.3, T=0.2, M=0.1, I=0.1}
Simplified version:
LinkedHashMap<Character, Double> sorted2 = tableProbability.entrySet().stream().sorted(Map.Entry.comparingByValue(Comparator.reverseOrder())).collect(LinkedHashMap::new, (col, e) -> col.put(e.getKey(), e.getValue()), HashMap::putAll);
System.out.println(sorted2); // {U=0.3, L=0.3, T=0.2, M=0.1, I=0.1}
See also: Ordering Map<String, Integer> by List<String> using streams
You may want to do it this way. It is common operation. If you want to return a TreeMap
, you can specify it below. And normally one assigns to the interface type. For a TreeMap
it would be NavigableMap
.
Map<Character, Double> sorted =
tableProbability.entrySet().stream()
.sorted(Map.Entry.comparingByValue(
Comparator.reverseOrder()))
.collect(Collectors.toMap(Entry::getKey,
Entry::getValue,
(a,b)->a, // merge, not used here but
// syntactically required
LinkedHashMap::new // type of map to return
));
Use a compound comparator:
.sorted(Map.Entry.comparingByValue(Comparator.reverseOrder())
.andThen(Map.Entry.comparingByKey())
)
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.