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Ok to delete element from HashMap while iterating?

Posted on 2009-07-13
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Last Modified: 2012-05-07
Hi,

Is it legal to remove an element from a HashMap while iterating over it? Something like:

  HashMap<Integer, String> test = new HashMap<Integer, String();
  test.put(0, "a");
  test.put(1, "b");
  test.put(2, "c");

  for(Entry<Integer, String> entry : test.entrySet()){
      if (entry.getValue().equals("b")) {
          test.remove(entry.getKey());
      }
      // Ok to keep iterating?
  }

Thanks
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Question by:DJ_AM_Juicebox
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3 Comments
 
LVL 92

Expert Comment

by:objects
ID: 24846020
you can but you need to use an Iterator and its remove() method'
How you are doing it will not work
0
 

Author Comment

by:DJ_AM_Juicebox
ID: 24846051
Ok but what do you mean with an iterator and a remove method?

Thanks
0
 
LVL 92

Accepted Solution

by:
objects earned 2000 total points
ID: 24846063
Iterator i = test.keySet().iterator();
while (i.hasNext()) {
     Integer key = i.next();
     String value = test.get(key);
     if (value.equals("b")) {
        i.remove();
    }
}
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