Table of Contents
Can you have a dictionary with duplicate keys?
Why you can not have duplicate keys in a dictionary? You can not have duplicate keys in Python, but you can have multiple values associated with a key in Python. If you want to keep duplicate keys in a dictionary, you have two or more different values that you want to associate with same key in dictionary.
Can Lookup have duplicate keys C#?
The answer is: yes.
Can a dictionary have two same keys but with different values?
No, each key in a dictionary should be unique. You can’t have two keys with the same value. Attempting to use the same key again will just overwrite the previous value stored. If a key needs to store multiple values, then the value associated with the key should be a list or another dictionary.
Is dictionary unique C#?
A dictionary, also called an associative array, is a collection of unique keys and a collection of values, where each key is associated with one value. Retrieving and adding values is very fast. Dictionaries take more memory because for each value there is also a key.
Can we add duplicate keys in Hashtable C#?
In hashtable, you can store elements of the same type and of the different types. 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.
Can Hashtable have duplicate keys C#?
Is Key in dictionary unique?
What happens when a dictionary has 2 items with the same key-value?
Does Hashtable allow duplicate keys?
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.
Which data structure prevents duplicates?
Any ideas to build a data structure without duplicating Employee objects in Map? Since you need to remove duplicates and also sort the list multiple times, better approach would be to use TreeSet . Advantage of using TreeSet is that, you will get distinct employees and also you will have employees in sorted order.
Can tuple hold duplicates?
Tuples A Tuple represents a collection of objects that are ordered and immutable (cannot be modified). Tuples allow duplicate members and are indexed.
Are dictionaries efficient C#?
The Dictionary is based on a hash table, that means it uses a hash lookup, which is a rather efficient algorithm to look up things, on the other hand, a list you have to go element by element until it finds the result from beginning to the result each time.
How to create a dictionary with duplicate keys in C?
[C#] Dictionary with duplicate keys. Sometimes there is a need to create a Dictionary with duplicates keys. The Key value of a Dictionary is unique and doesn’t let you add a duplicate key entry. To accomplish the need of duplicates keys, i used a List of type KeyValuePair<>. For example if you have to add a string with multiple values:
How do you have multiple values in a dictionary?
What you can do is have each key refer to multiple values (logically, not technically). This is done by having a dictionary in which the value is a data structure of some sort (for example, a List) that contains all of the values that correspond to that particular key.
How to get the value of every key in a dictionary?
Every key in a Dictionary must be unique according to the dictionary’s equality comparer. Possible solutions – you can keep collection of strings as value (i.e. use Dictionary > ), or (better) you can use Lookup instead of dictionary.
How do I link multiple keys to a dictionary?
In a dictionary each key is unique and mapped to a single value. If you want to link an object to an arbitrary number of additional objects, the best bet might be something akin to a DataSet (in common parlance a table). Put your keys in one column and your values in the other.