Dictionary

A series of key-value pairs. Object –> Dictionary<TKey, TValue>

Type safe. Invalid key throws exception. Namespace
System.Collections.Generic Implements
IDictionary<TKey, TValue>

Items in a dictionary are instances of a struct.

other dictionaries

SortedDictionary<TKey, TValue> A collection of key/value pairs that are sorted by key.

Construction`

Dictionary<key-type, value-type> d = new();
// or
Dictionary<TKey, TValue> d = new() 
{
    { key1, value1 }
    …
};

accessing

d[key]

iterating

foreach (KeyValuePair<TKey, TValue> item in d) 
{
    Console.WriteLine($"{item.Key}: {item.Value}");
}

methods

manipulating

.Add(key, value);
.Add(key: k, value: v);

searching

.ContainsKey(key) // Return boolean if key is in dictionary.
.ContainsValue(value) // Return boolean if value is in dictionary.
.TryGetValue(key, out var1) // Retrieve value at key and store it in var1.

properties

.CountReturn number of k:v pairs. .KeysReturn the keys. .ValuesReturn the values.