itertools

A PHP port of Python's itertools, built on generators.

Requires PHP 8.4+. All itertools helpers are implemented, plus iter, enumerate, and range.

Install

composer require bolknote/itertools

Usage

use Itertools\Itertools as it;

foreach (it::islice(it::cycle('ABC'), 10) as $element) {
    echo $element; // ABCABCABCA
}

Strings are treated as sequences of characters (like Python), alongside arrays and any Traversable.

Highlights

Area	Methods
Infinite / slicing	count, cycle, repeat, islice
Terminating	accumulate, batched, chain, chain_from_iterable, compress, dropwhile, filterfalse, groupby, ifilter, imap, izip, izip_longest, pairwise, starmap, takewhile, tee
Combinatoric	product, permutations, combinations, combinations_with_replacement
Extras	iter, enumerate, range

Notes:

• izip_longest(...$iterables, $fillvalue) — fill value is the last argument (PHP has no keyword-only params after a variadic).
• product(...$iterables, $repeat) — if the last argument is an int, it is Python's repeat.
• groupby yields [key, list] pairs (groups are materialized arrays).
• tee shares a buffer so clones can be consumed independently / interleaved.
• accumulate(..., $initial = null) — like Python, null means “no initial value”.

Development

composer update
composer test      # PHPUnit
composer phpstan   # static analysis