Do we have any other way to add an element into Map without using put() in Java? If there are other ways, how do we do it?
Map<String,String> map = new HashMap<String,String>();
map.put("hi","HI");
How can we add without using put() in this case?
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4you mean with a shovel? – Mar 01 '15 at 15:23
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there exist a method called putAlll. But that is not exactly the same http://docs.oracle.com/javase/7/docs/api/java/util/Map.html#putAll(java.util.Map) – Thusitha Thilina Dayaratne Mar 01 '15 at 15:24
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You can use the methods `replace` and `putIfAbsent` ... *if* you're using java 8. – fabian Mar 01 '15 at 15:30
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2You probably should not be using `Map` if you want other ways of adding an element. – tourniquet_grab Mar 01 '15 at 15:36
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If you're asking for `Map` literals (something like `Map
map = {1="Hi", 2="Hello"};`) the answer is that you just can't do that. Lots of tedious calls to `put` is unfortunately how you have to initialise a `Map` at the moment. – Paul Boddington Mar 01 '15 at 16:07 -
What's wrong with put()? Why do you want to avoid using it? Why don't you read the javadoc, which would answer this question? – JB Nizet Mar 01 '15 at 16:24
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You can specify initial content in the constructor. But internally it all boils down to some form of put, of course. – eckes Mar 02 '15 at 00:23
2 Answers
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put and putAll are the only two methods for adding new hash entries in Java. If you're looking for a Ruby or Python style way of doing it such as hash['x'] = 'hello world';, then you are going to need to use a JVM language like JRuby or Groovy.
Mike Thomsen
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There is no way to change HashMap content without calling put() or other mutation methods. Probably, you are looking for double brace initialization. For more info, see this answer.
