How to make an iterator rewindable with Iter?

Use iter\makeRewindable to wrap functions like map, or prefix with iter\rewindable\ (e.g., rewindable\map). This allows multiple passes over generator-based iterators, but adds overhead compared to native arrays.

Iter vs Laravel Collections: which is better?

Iter is lightweight and works with any iterable using lazy evaluation, ideal for pure PHP projects. Laravel Collections offer more features like eager methods and integration with Laravel, but are tied to that framework and less memory-efficient for large data.

When should I use Iter over array_map in PHP?

Use Iter when working with non-array iterables like generators or when you need lazy evaluation to save memory. array_map is faster for small arrays but only handles arrays and creates intermediate arrays eagerly.

Does Iter work with PHP 8 features like fibers?

Iter is built on generators and compatible with PHP 5.5+, but it doesn't explicitly integrate with newer features like fibers. It focuses on iteration primitives, so advanced concurrency would require other libraries.

How to chain multiple operations with Iter?

Chain functions like map, filter, and reduce directly in a pipeline since they return iterators. For example: iter\map(fn($x) => $x*2, iter\filter(fn($x) => $x > 0, $data)). This maintains laziness throughout.

Is Iter suitable for real-time data processing?

Yes, due to lazy evaluation, it can handle streaming data efficiently. However, for low-latency requirements, the generator overhead might be a concern compared to optimized array operations in tight loops.

Open-Awesome

Iter

NOASSERTIONPHPv2.4.1

A PHP library providing iteration primitives like map and filter using generators, working with any iterable type.

GitHub

1.1k stars69 forks0 contributors

What is Iter?

Iter is a PHP library that provides iteration primitives like map, filter, and reduce using generators. It solves the problem of performing functional operations on any iterable type—not just arrays—while maintaining lazy evaluation for memory efficiency.

Target Audience

PHP developers working with iterators, generators, or functional programming patterns who need consistent iteration utilities across different iterable data structures.

Value Proposition

Developers choose Iter because it offers a unified, lazy approach to iteration that works with arrays, traversables, and custom iterators, unlike native PHP array functions or SPL iterators which are more limited in scope.

Overview

Iteration primitives using generators

Use Cases

Best For

Applying functional operations to PHP generators or iterators
Working lazily with large datasets to reduce memory usage
Creating reusable iteration pipelines across different iterable types
Implementing functional programming patterns in PHP codebases
Extending iteration capabilities beyond standard array functions
Building rewindable generator-based iterators for multiple passes

Not Ideal For

Projects exclusively using arrays that don't benefit from lazy iteration
Applications requiring eager evaluation for immediate full result sets
Teams needing a fully-featured functional programming library with monads or currying
Scenarios where performance overhead from generator abstraction is unacceptable

Pros & Cons

Pros

Universal Iterable Support

Functions work with arrays, traversables, iterators, and aggregates, unlike native array_map or SPL iterators that are limited, enabling consistent code across data structures.

Lazy Evaluation Efficiency

Operations use PHP generators to process data on-demand, reducing memory usage for large datasets compared to eager array functions that create intermediate arrays.

Comprehensive Function Set

Includes map, filter, reduce, zip, chain, and over 30 other primitives, providing a wide range of functional iteration tools directly in the library.

Rewindable Generator Utilities

Offers makeRewindable and rewindable prefixes to handle multiple passes over generator-based iterators, addressing a common limitation of default generators.

Cons

Non-Rewindable By Default

Generators are inherently non-rewindable, requiring extra steps like rewindable wrappers for reuse, which adds complexity compared to native arrays or SPL iterators.

Sparse Documentation

Usage examples are minimal in the README; developers must read the source file iter.php for details, making onboarding harder than with fully documented libraries.

Limited Functional Extensions

Focuses solely on iteration primitives without advanced functional features like partial application or monadic operations, which might require additional libraries.

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