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Hashmap

akshitha Akki
Greenhorn

Joined: Aug 03, 2012
Posts: 24
HashMap stores the contents in a key value pairs.So is it possible to store set of 'keys' in one arraylist, set of values in another arraylist and then send these arraylists to hashmap.
Gave a try to do the same. But did not get the concept of how the arraylist contents gets stored in HashMap.

Example:
Arraylist first has set of key - apple, orange, papaya
Arraylist second has set of values - red, yellow, green

so now the two arraylists have to be passed to hash map
HashMap<ArrayList, ArrayList> test = new HashMap<ArrayList, ArrayList>()

Can someone please help to get the concept of how the contents gets stored in arraylist and HashMap.
Henry Wong
author
Sheriff

Joined: Sep 28, 2004
Posts: 18745
    
  40

akshitha Akki wrote:HashMap stores the contents in a key value pairs.So is it possible to store set of 'keys' in one arraylist, set of values in another arraylist and then send these arraylists to hashmap.
Gave a try to do the same. But did not get the concept of how the arraylist contents gets stored in HashMap.

Example:
Arraylist first has set of key - apple, orange, papaya
Arraylist second has set of values - red, yellow, green

so now the two arraylists have to be passed to hash map
HashMap<ArrayList, ArrayList> test = new HashMap<ArrayList, ArrayList>()

Can someone please help to get the concept of how the contents gets stored in arraylist and HashMap.


I don't think that the core library has anything that does it automatically -- but you can easily write code that loops through the arraylists to add the pairs to the hashmap.

Henry


Books: Java Threads, 3rd Edition, Jini in a Nutshell, and Java Gems (contributor)
akshitha Akki
Greenhorn

Joined: Aug 03, 2012
Posts: 24
Yes I did try to do that, but i was unable to get the name from one arraylist, value from another arraylist and store them in a hashmap at the same time.Can I get a hint to get that concept so that I can do that.
Paul Clapham
Bartender

Joined: Oct 14, 2005
Posts: 18541
    
    8

Really? You can't come up with any code which iterates through a list? Because that would be your first step, wouldn't it? Remember that your requirement is "Iterate through two ArrayLists and..." so iterating would be the first thing to work on.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: Hashmap