Can you explain what a data structure is and why it is needed?

Data structures are methods of organizing and storing data in a computer's memory to ensure efficient access and modification of that data. They are necessary for programs to work quickly and conveniently with information: searching, adding, deleting, or modifying elements.

For example, in Flutter, you can use a list (List) to store a set of elements, or a map (Map) to store key-value pairs. Choosing the right data structure affects performance and development convenience.