Is HashSet same as Dictionary?
They both share more or less the same asymptotic complexity for all the operations. The real difference is the fact that with a Dictionary we can create key-value pairs (with the keys being unique), while with an HashSet we’re storing an unordered set of unique items.
Is Dictionary faster than HashSet?
Here is the code for the same. and results are. Fetching results from HashSet is fastest followed by SortedSet then Dictionary and finally List. As part of this test, I am removing only 1 item for the types and capturing respective time taken to perform the task.
Is a Dictionary a hash table C#?
The Dictionary class is a type-safe Hashtable implementation, and the keys and values are strongly typed. When creating a Dictionary instance, you must specify the data types for both the key and value. Dictionary is NOT implemented as a HashTable, but it is implemented following the concept of a hash table.
What can I use instead of Dictionary in C#?
A HashSet, similar to a Dictionary, is a hash-based collection, so look ups are very fast with O(1). But unlike a dictionary, it doesn’t store key/value pairs; it only stores values. So, every objects should be unique and this is determined by the value returned from the GetHashCode method.
Is HashSet faster than List?
Yes a linear search of a List will beat a HashSet for a small number of items. But the performance difference usually doesn’t matter for collections that small. It’s generally the large collections you have to worry about, and that’s where you think in terms of Big-O.
Why do we use Dictionary in C#?
In C#, Dictionary is a generic collection which is generally used to store key/value pairs. The working of Dictionary is quite similar to the non-generic hashtable. The advantage of Dictionary is, it is generic type. Dictionary is defined under System.
Why Dictionary is used in C#?
What is ordered Dictionary in C#?
Remarks. Each element is a key/value pair stored in a DictionaryEntry object. A key cannot be null , but a value can be. The elements of an OrderedDictionary are not sorted by the key, unlike the elements of a SortedDictionary class. You can access elements either by the key or by the index.