Dictionary<TKey, TValue>
provide fast lookups, based on keys, to get values. With them, we use keys and values of any type, including int and string. Dictionary is used with different elements. We specify its key type and its value type (string, int).
Define a Dictionary
We specify its key type and its value type (string, int).
Add elements to a Dictionary
Here’s how to add elements to a Dictionary
.
Read and update existing values
To read a value use the following statement.
To update an existing value simply use the following.
Check if a key exists in a Dictionary
This sees if a given string is present in a Dictionary.
Iterate through a Dictionary
Here we loop over KeyValuePairs
in a Dictionary
. With collections like Dictionary
, we must always know the value types. With each KeyValuePair
, there is a Key
member and Value
member.
Remove elements from a Dictionary
Here’s how you can remove elements from a Dictionary
.
Count elements in a Dictionary
This computes the total number of keys in a Dictionary
. This is simpler than accessing the Keys
property, or looping over the Dictionary
to count it.
Clear all elements from a Dictionary
We can erase all pairs with the Clear
method.
Check if a value exists in a Dictionary
This method lacks the constant-time look up speed of ContainsKey. It instead searches the entire collection.
Get all keys of a Dictionary
Here we use the Keys property. We then look through each key and look up the values.
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