4.2.7 Dictionaries

Question 1

Define Dictionaries.

Answer 1

A collection of key-value pairs in which the key value is accessed via the associated key.
Dictionary is unordered as value is retrieved by key than position.

Question 2

What are some standard dictionary operations?

Answer 2

• retrieve a value associated with a particular key
• insert a new key-value pair into the collection
• remove a key-value pair from the collection
• update a value associated with a key

Question 3

How does using a key make dictionaries operate more efficiently?

Answer 3

Using a key allows direct access to items stored within the collection.
This provides much quicker access to unordered data than searching through the data set using a linear search and will also outperform a binary search.

Key-value retrieval is a technique widely used in various high-performance systems, such as caches and databases.

Question 4

How to retrieve a value from the dictionary?

Answer 4

To retrieve a value, you must use the key, this will return the associated data value.
The key is used in the same way that an index is used for an array.