CODEWITHSUNDEEP
javaarrayshashmapjava-stream
Garry Steve
Garry Steve

Reputation: 129

Inserting elements into map using streams

I have a 

List<String> lists;

I need to iterate through this lists and put in the LinkedHashMap. Normally I do it as below:

Map<Integer,String> listMap=new LinkedHashMap<>();
for(int pos=0;pos<lists.size();pos++){
    listMap.put(pos,lists.get(pos));
}

How can I do the above operation with streams?

Upvotes: 2

Views: 3299

Answers (1)

Eran
Eran

Reputation: 393811

Use Collectors.toMap on a Stream<Integer> of the List's indices:

Map<Integer,String> listMap =
   IntStream.range(0,lists.size())
            .boxed()
            .collect(Collectors.toMap(Function.identity(),
                                      lists::get,
                                      (a,b)->a,
                                      LinkedHashMap::new));

P.S., the output Map is a Map<Integer,String>, which fits the for loop in your question (unlike the specified Map<Integer,List<String>>, which doesn't, unless you change the input List from List<String> to List<List<String>>).

Upvotes: 5

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