Accessing a value by index requires a translation between the index and its corresponding position in the buffer: ((head position) capacity).

The array is a complex, flexible, master-of-none, hybrid data structure, combining the behaviour of a list and a linked map.

The recent release of PHP 7 caused a lot of excitement in the PHP community.

We couldnt wait to start using the new features and try out the reported 2x performance boost.

One of the reasons why it runs that much faster is because the array was redesigned.

But its still the same structure, optimised for everything; optimised for nothing with room for improvement.

What about the SPL data structures Unfortunately they are terrible.

They did offer some benefits prior to PHP 7, but have since been neglected to the point of having no practical value.

Why cant we just fix and improve them We could, but I believe their design and implementation is so poor that it would be better to replace them with something brand new.

Anthony Ferrara Introducing ds, an extension for PHP 7 providing specialized data structures as an alternative to the array.

This post briefly covers the behaviour and performance benefits of each structure.

There is also a list of answers to expected questions at the end.

Github: Namespace: Ds Interfaces: Collection, Sequence, Hashable Classes: Vector, Deque, Map, Set, Stack, Queue, PriorityQueue, Pair Collection Collection is the base interface which covers common functionality like foreach, echo, count, printr, vardump, serialize, jsonencode, and clone.

Sequence Sequence describes the behaviour of values arranged in a single, linear dimension.

Its similar to an array that uses incremental integer keys, with the exception of a few characteristics: Values will always be indexed as 0, 1, 2,, size - 1.

Removing or inserting updates the position of all successive values.

Only allowed to access values by index in the range 0, size - 1.

Vector A Vector is a Sequence of values in a contiguous buffer that grows and shrinks automatically.

Its the most efficient sequential structure because a values index is a direct mapping to its index in the buffer, and the growth factor isnt bound to a specific multiple or exponent.

Strengths Very low memory usage get, set, push and pop are O(1) Weaknesses insert, remove, shift, and unshift are O(n) The number one data structure used in Photoshop was Vectors.

Sean Parent, CppCon 2015 Deque A Deque (pronounced deck ) is a Sequence of values in a contiguous buffer that grows and shrinks automatically.

The name is a common abbreviation of double-ended queue and is used internally by DsQueue.

The pointers can wrap around the end of the buffer, which avoids the need to move other values around to make room.

This makes shift and unshift very fast something a Vector cant compete with.

Dmg Track Ds Vs Spl