CODEWITHSUNDEEP
javamaps
AndyReifman
AndyReifman

Reputation: 1834

Updating one Map key from another map Value

I have one HashMap called list which contains a few key/values. I've got another HashMap called modify which contains another set of key/values.

Basically the modify hashmap is supposed to contain a key (or keys) that match to a key in list, and I want to update the key in list to be the value that matches that key in modify.

I tried:

iter = modifyList.entrySet().iterator();
while(iter.hasNext()) {
     list.replace(iter.next().getKey(), iter.next().getValue());
}

However you run in to the issue where when you call iter.next().getKey() it obviously iterates forward so now the value that I want is no longer in next() and is instead in current. However I can't find any way to access what is in current

Does anyone have any suggestions on the best way to accomplish this?

Upvotes: 0

Views: 1001

Answers (1)

jspcal
jspcal

Reputation: 51894

Try iterating over the key and value:

modifyList.forEach(list::replace);

Which is the same as:

modifyList.forEach((k, v) -> list.replace(k, v));

Now if you're looking to remap the keys themselves, you can use a combination of put and remove:

modifyList.forEach((k, v) -> list.put(v, list.remove(k)));

Upvotes: 2

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