What is a data structure?

A data structure is a way of organizing and storing data in a computer's memory so that it can be conveniently and efficiently accessed, modified, and processed.

Different data structures solve different problems:

• an array is convenient for fast access by index;
• a list is for frequent insertions and deletions;
• a dictionary (hash table) is for fast lookup by key;
• a tree is for hierarchies and fast searches;
• a queue and a stack are for ordered processing of elements.

In other words, a data structure determines exactly how data is stored and what can be done with it quickly.