What Is Association List in Data Structure?


Angela Bailey

What Is Association List in Data Structure?

In data structure, an association list is a type of list that stores key-value pairs. It is a flexible and dynamic data structure that allows for efficient retrieval and modification of values based on their corresponding keys.

Structure of an Association List

An association list is typically implemented as a linked list, where each node contains a key-value pair. The key represents the identifier or label, while the value represents the associated data. The nodes are connected sequentially, allowing for easy traversal and access to the elements.


Consider an association list that stores information about fruits:

  • Node 1: Key: “apple” | Value: “red”
  • Node 2: Key: “banana” | Value: “yellow”
  • Node 3: Key: “orange” | Value: “orange”

In this example, each node contains a key-value pair representing a specific fruit and its corresponding characteristic (color).

Operations on Association Lists

An association list supports various operations for manipulating and accessing its elements. Some common operations include:

  • Insertion: Adding a new key-value pair to the association list.
  • Deletion: Removing a specific key-value pair from the association list.
  • Lookup: Retrieving the value associated with a given key.
  • Modification: Updating the value associated with a specific key.

The performance of these operations depends on the implementation and the size of the association list. In general, insertion and deletion operations can be efficient in a linked list-based implementation, while lookup and modification operations may require traversing the entire list.

Applications of Association Lists

Association lists find applications in various domains, including:

  • Symbol tables: In programming languages, association lists are commonly used to implement symbol tables that store variables and their corresponding values.
  • Configuration settings: Association lists can be used to store and manage configuration settings in software applications.
  • Dictionary: Association lists can be utilized as a simple dictionary to store word definitions.

The flexibility and simplicity of association lists make them a valuable tool for managing key-value data in different scenarios.


An association list is a versatile data structure that allows for efficient storage, retrieval, and modification of key-value pairs. It provides a flexible approach to managing data relationships and finds applications in various fields. By understanding the structure and operations of association lists, you can enhance your ability to handle key-value data effectively.

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