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convert a ArrayList to a Hashmap

Posted on 2006-11-07
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Last Modified: 2008-02-01
hi experts

i have a requirment where i have to convert a ArrayList to a Hashmap

want to know if thats possible

here is a code snippet
ArrayList judgeObjects = (ArrayList)request.getAttribute("judges"); //judges is of type list
Iterator judgeIterator=  judgeObjects.iterator();
while (judgeIterator.hasNext ()) {
    HashMap judegenames = judgeIterator.next(); //want to save ArrayList objects in Hashmap.// Any ideas ?....

....
}
0
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Question by:jaggernat
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7 Comments
 
LVL 23

Accepted Solution

by:
Ajay-Singh earned 400 total points
ID: 17892257
try this:

Map map = new HashMap();
ArrayList judgeObjects = (ArrayList)request.getAttribute("judges");Iterator judgeIterator=  judgeObjects.iterator();
while (judgeIterator.hasNext ()) {
    HashMap judegenames = judgeIterator.next(); //want to save ArrayList objects in Hashmap.// Any ideas ?....
    map.putAll(judegenames);
....
}
0
 
LVL 10

Author Comment

by:jaggernat
ID: 17892353
works ..thanks.

one general question.

is ther any specific use of Hashmap over arraylist or vice-versa.
Can i just use Arraylist instead of using Hashmap in while loop
 (  HashMap judegenames = judgeIterator.next();
    map.putAll(judegenames);
 )
0
 
LVL 23

Expert Comment

by:Ajay-Singh
ID: 17892616
> is ther any specific use of Hashmap over arraylist or vice-versa.
HashMap (or Map in general) is used to store key - value pairs whereas List stores list of objects
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LVL 23

Expert Comment

by:Ajay-Singh
ID: 17892636
> Can i just use Arraylist instead of using Hashmap in while loop
Well depends on the usage, if you want only either key or values of the judegenames, then you can use ArrayList
otherwise Map should be used
0
 
LVL 10

Author Comment

by:jaggernat
ID: 17892664
while (judgeIterator.hasNext ()) {
    HashMap judegenames = judgeIterator.next(); //want to save ArrayList objects in Hashmap.// Any ideas ?....
    map.putAll(judegenames);
....
}



for the above code , can i just use arraylist instead of hashmap. which one is a better choice

thanks
0
 
LVL 23

Expert Comment

by:Ajay-Singh
ID: 17892695
> for the above code , can i just use arraylist instead of hashmap. which
> one is a better choice
see above
0
 
LVL 10

Author Comment

by:jaggernat
ID: 17892701
thanks
0

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