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Want to Add Duplicate Key in HashMap
Hi,
I am trying to add duplicate key in HashMap.
For eg:-HashMap<String,HashMap<String,String>> empMap=new HashMap<String,HashMap<String,String>>();
I wan to add EmployeeId as key and inner hash map will will DOB and the value.I am trying to store some thing like,
{101OB:20/10/1985,102
But when I try this using hashmap the value of DOB is overwriting
Any suggestions?
Thanks in Adv
Ram
Related threads:
Re: Want to Add Duplicate Key in HashMap
If you want more than one value for a key, make the value a list. To add an item, get the value/list and add the new item to the list.
If you don't understand my answer, don't ignore it, ask a question.
Re: Want to Add Duplicate Key in HashMap
Originally Posted by rampnq
A Map by definition does not allow duplicate keys. I recommend posting an SSCCE, as the posted values - presuming I am reading them correctly - should store fine within the data structure posted if accessed correctly
Re: Want to Add Duplicate Key in HashMap
To my understanding of your problem, you have an employee id as the key in your HashMap, and then employee information (which is also stored in a HashMap) in your HashMap's value. Out of curiosity, is there a good reason you are storing the employee information (such as DOB) in a HashMap instead of an object?
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Re: Want to Add Duplicate Key in HashMap
HashMap allows the duplicate keys and override the value with the lastest value of duplicate Key.
Like Here you are using OB key in inner hashmap so this might be overriding the value of inner class.
Thanks,
Re: Want to Add Duplicate Key in HashMap
HashMap does not allow duplicate keys.It allows at max one key with null value.
Re: Want to Add Duplicate Key in HashMap
You can't have duplicate keys in a HashMap. You can, however, create a "multimap" -- a map with Lists as values.
Re: Want to Add Duplicate Key in HashMap
Yes. It overwrites it because a map cannot contain duplicate keys. Each key can map up to only one value. Say you're inputing emails, for each email, there is only one value to each key on the hash table. Your most recent email entered is overwritten. Only one value on that map. Understood?
Re: Want to Add Duplicate Key in HashMap
The person starting this thread did so 4 years ago. They didn't answer a direct question, nor did they respond to the useful advice they were given at the time. In fact, they though so little of their own thread that they were never heard from again.
It seems less than pointless to revive a thread that has been long dead - and which did no more than stagger a little and then drop from exhaustion during its brief life. Closing.
