C# Dictionaries

Dictionaries are used in C# to define key value pairs. They are part of System.Collections.Generic.

The format is:

Dictionary<key,value>

To define a dictionary, use the format:

Dictionary<datatype, datatype> d = new Dictionary<datatype, datatype>();

For example:

Dictionary<int, int> d = new Dictionary<int, int>();

or

Dictionary<string, int> d = new Dictionary<string, int>();

To add to the data type, you can do either:

Dictionary<string, int> d1 = new Dictionary<string, int>();
d1.Add("Bob", 12345);

or

d[3] = 30;

From there, you can use different methods on the dictionary such as ContainsKey, ContainsValue:

if (d.ContainsKey(2))
{
    Console.WriteLine(d[2]);
}

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Carl de Souza Enterprise Architect at Microsoft · AI Technology Expert