Iteration primitives using generators
This library implements iteration primitives like map() and filter()
using generators. To a large part this serves as a repository for small
examples of generator usage, but of course the functions are also practically
quite useful., (*1)
All functions in this library accept arbitrary iterables, i.e. arrays,
traversables, iterators and aggregates, which makes it quite different from
functions like array_map() (which only accept arrays) and the SPL iterators
(which usually only accept iterators, not even aggregates). The operations are
of course lazy., (*2)
Install
To install with composer:, (*3)
composer require nikic/iter
Functionality
A small usage example for the map() and range() functions:, (*4)
<?php
use iter\func;
require 'path/to/vendor/autoload.php';
$nums = iter\range(1, 10);
$numsTimesTen = iter\map(func\operator('*', 10), $nums);
// => iter(10, 20, 30, 40, 50, 60, 70, 80, 90, 100)
You can find documentation and usage examples for the individual functions in
iter.php, here I only
list the function signatures as an overview:, (*5)
Iterator map(callable $function, iterable $iterable)
Iterator mapWithKeys(callable $function, iterable $iterable)
Iterator mapKeys(callable $function, iterable $iterable)
Iterator flatMap(callable $function, iterable $iterable)
Iterator reindex(callable $function, iterable $iterable)
Iterator filter(callable $predicate, iterable $iterable)
Iterator enumerate(iterable $iterable)
Iterator toPairs(iterable $iterable)
Iterator fromPairs(iterable $iterable)
Iterator reductions(callable $function, iterable $iterable, mixed $startValue = null)
Iterator zip(iterable... $iterables)
Iterator zipKeyValue(iterable $keys, iterable $values)
Iterator chain(iterable... $iterables)
Iterator product(iterable... $iterables)
Iterator slice(iterable $iterable, int $start, int $length = INF)
Iterator take(int $num, iterable $iterable)
Iterator drop(int $num, iterable $iterable)
Iterator takeWhile(callable $predicate, iterable $iterable)
Iterator dropWhile(callable $predicate, iterable $iterable)
Iterator keys(iterable $iterable)
Iterator values(iterable $iterable)
Iterator flatten(iterable $iterable, int $levels = INF)
Iterator flip(iterable $iterable)
Iterator chunk(iterable $iterable, int $size, bool $preserveKeys = false)
Iterator chunkWithKeys(iterable $iterable, int $size)
Iterator tap(callable $function, iterable $iterable)
Iterator toIter(iterable $iterable)
Iterator range(number $start, number $end, number $step = null)
Iterator repeat(mixed $value, int $num = INF)
Iterator split(string $separator, string $data)
mixed reduce(callable $function, iterable $iterable, mixed $startValue = null)
bool any(callable $predicate, iterable $iterable)
bool all(callable $predicate, iterable $iterable)
mixed search(callable $predicate, iterable $iterable)
void apply(callable $function, iterable $iterable)
string join(string $separator, iterable $iterable)
int count(iterable $iterable)
bool isEmpty(iterable $iterable)
mixed recurse(callable $function, $iterable)
array toArray(iterable $iterable)
array toArrayWithKeys(iterable $iterable)
bool isIterable($value)
As the functionality is implemented using generators the resulting iterators
are by default not rewindable. This library implements additional functionality
to allow creating rewindable generators., (*6)
You can find documentation for this in iter.rewindable.php,
here is just a small usage example of the two main functions:, (*7)
<?php
use iter\func;
require 'path/to/vendor/autoload.php';
/* Create a rewindable map function which can be used multiple times */
$rewindableMap = iter\makeRewindable('iter\\map');
$res = $rewindableMap(func\operator('*', 3), [1, 2, 3]);
/* Do a rewindable call to map, just once */
$res = iter\callRewindable('iter\\map', func\operator('*', 3), [1, 2, 3]);
The above functions are only useful for your own iterators though; for the
iter iterators, rewindable variants are directly provided with an
iter\rewindable prefix:, (*8)
$res = iter\rewindable\map(func\operator('*', 3), [1, 2, 3]);
// etc
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