Table of Contents
- 1 Can I store duplicate values in HashMap or Hashtable?
- 2 Can two keys have same value in HashMap?
- 3 Does Hashtable allow duplicate values?
- 4 Can we add duplicate value and keys in hash table?
- 5 Can one key have multiple values?
- 6 Are Keys unique in Hashtable?
- 7 How to store a list of integers in a hashmap?
- 8 Is it legal for two objects to have the same hash code?
Can I store duplicate values in HashMap or Hashtable?
Differences:
HashSet | HashMap |
---|---|
HashSet does not allow duplicate elements that means you can not store duplicate values in HashSet. | HashMap does not allow duplicate keys however it allows to have duplicate values. |
HashSet permits to have a single null value. | HashMap permits single null key and any number of null values. |
Can two keys have same value in HashMap?
HashMap can be used to store key-value pairs. But sometimes you may want to store multiple values for the same key. For example: For Key A, you want to store – Apple, Aeroplane.
Can Hashtable have same key?
A Hashtable does not accept duplicate keys. If you add a duplicate key the value will be replaced for that key. Here, you can see that when the key 1 is added again, the value is replaced with Kumaran. So, Hashtable does not accept duplicate keys.
Does Hashtable allow duplicate values?
Hashtable Features It does not accept duplicate keys. It stores key-value pairs in hash table data structure which internally maintains an array of list.
Can we add duplicate value and keys in hash table?
it can have duplicate values but not keys. If you wanted to associate multiple values with a key, you could place a reference to an array (or hash) at that key, and add the value to that array (or hash).
Can HashMap have same values?
Duplicates: HashSet doesn’t allow duplicate values. HashMap stores key, value pairs and it does not allow duplicate keys.
Can one key have multiple values?
In python, if we want a dictionary in which one key has multiple values, then we need to associate an object with each key as value. This value object should be capable of having various values inside it. We can either use a tuple or a list as a value in the dictionary to associate multiple values with a key.
Are Keys unique in Hashtable?
The elements of hashtable that is a key/value pair are stored in DictionaryEntry, so you can also cast the key/value pairs to a DictionaryEntry. In Hashtable, key must be unique. Duplicate keys are not allowed.
Why do my hashmaps have the same value but different keys?
Same values with different keys in a hashmap. Initially, I put two entries with the same value into a hashmap. The value of the two entries is itself a map. These entries have different keys. Basically, the issue is that you did not put two maps into your map, but rather put two references to the same map.
How to store a list of integers in a hashmap?
To store this data in a lookup table / map , we need to create a HashMap with key as string and then associate multiple values with same key. We can do this by storing a List of Integers i.e. List objects as values in HashMap.
Is it legal for two objects to have the same hash code?
It’s perfectly legal for two unequal objects to have the same hash code. It’s used by HashMap as a “first pass filter” so that the map can quickly find possible entries with the specified key. The keys with the same hash code are then tested for equality with the specified key.
How does hashmultimap work?
Take a look at Multimap from the guava-libraries and its implementation – HashMultimap A collection similar to a Map, but which may associate multiple values with a single key. If you call put (K, V) twice, with the same key but different values, the multimap contains mappings from the key to both values.