Iterating through a LinkedHashMap in reverse order

java hashmap linkedhashmap
Dominic Bou-Samra picture Dominic Bou-Samra · Aug 24, 2011 · Viewed 26.4k times · Source

I have a LinkedHashMap:

LinkedHashMap<String, RecordItemElement>

that I need to iterate through from a given key's position, backwards. So if I was given the 10th item's key, I'd need iterate backwards through the hashmap 9, 8, 7 etc.

Answer

user2274508 picture user2274508 · Feb 17, 2016

The question requires a LinkedHashMap in reverse order, some answers suggesting using a TreeSet but this will reorder the map based upon the key.

This solution allows the iteration over the original LinkedHashMap not the new ArrayList as has also been proposed:

List<String> reverseOrderedKeys = new ArrayList<String>(linkedHashMap.keySet());
Collections.reverse(reverseOrderedKeys);
for (String key : reverseOrderedKeys) {
    RecordItemElement line = linkedHashMap.get(key);
}

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