ArrayList and LinkedList in Haskell

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Haskell Lists<br>
Haskell Lists<br>

In Haskell, the concept of ArrayList and LinkedList, as they are known in Java, doesn't directly apply because Haskell, being a functional programming language, handles data structures and their behaviors quite differently from Java, which is object-oriented.

List in Haskell

Haskell's primary list structure resembles a singly linked list. It is not called LinkedList, but simply a list, denoted by square brackets (e.g., [1, 2, 3]). This list is efficient for operations like adding or removing elements at the head but can be less efficient for random access or modifications due to the need to traverse the list.

Array Structures in Haskell

Haskell doesn't have a direct equivalent to Java's ArrayList. However, it offers several array-like structures through various libraries. For instance, the Array type from the array package provides an immutable array structure, and the Vector type from the vector package offers both mutable and immutable arrays. These structures are more similar to Java's arrays in terms of providing indexed access to elements

Performance Characteristics

The performance characteristics in Haskell for lists and array-like structures are similar to the differences between LinkedList and ArrayList in Java. Lists in Haskell are good for sequential access and operations at the head, while array-like structures in Haskell provide efficient random access.


A major difference in Haskell is the emphasis on immutability. Unlike Java, where you can modify the elements of an ArrayList or LinkedList in place, Haskell's data structures are typically immutable, meaning you create new structures rather than modifying existing ones.

Functional Approach

Haskell's approach to handling these structures is functional, meaning operations on lists and arrays are often done using recursion and higher-order functions like map, filter, and fold, rather than the imperative loop-based approaches common in Java.


In summary, while Haskell has list and array-like structures with performance characteristics similar to LinkedList and ArrayList in Java, the way they are used and implemented is quite different, reflecting Haskell's functional programming paradigm.

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