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PHP code example of markrogoyski / itertools-php

1. Go to this page and download the library: Download markrogoyski/itertools-php library. Choose the download type require.

2. Extract the ZIP file and open the index.php.

3. Add this code to the index.php.

    
        
<?php
require_once('vendor/autoload.php');

/* Start to develop here. Best regards https://php-download.com/ */

markrogoyski / itertools-php example snippets


foreach (Multi::zip(['a', 'b'], [1, 2]) as [$letter, $number]) {
    print($letter . $number);  // a1, b2
}


$result = Stream::of([1, 1, 2, 2, 3, 4, 5])
    ->distinct()                 // [1, 2, 3, 4, 5]
    ->map(fn ($x) => $x**2)      // [1, 4, 9, 16, 25]
    ->filter(fn ($x) => $x < 10) // [1, 4, 9]
    ->toSum();                   // 14


use IterTools\Multi;

$prequels  = ['Phantom Menace', 'Attack of the Clones', 'Revenge of the Sith'];
$originals = ['A New Hope', 'Empire Strikes Back', 'Return of the Jedi'];

foreach (Multi::chain($prequels, $originals) as $movie) {
    print($movie);
}
// 'Phantom Menace', 'Attack of the Clones', 'Revenge of the Sith', 'A New Hope', 'Empire Strikes Back', 'Return of the Jedi'


use IterTools\Multi;

$languages = ['PHP', 'Python', 'Java', 'Go'];
$mascots   = ['elephant', 'snake', 'bean', 'gopher'];

foreach (Multi::zip($languages, $mascots) as [$language, $mascot]) {
    print("The {$language} language mascot is an {$mascot}.");
}
// The PHP language mascot is an elephant.
// ...


$names          = ['Ryu', 'Ken', 'Chun Li', 'Guile'];
$countries      = ['Japan', 'USA', 'China', 'USA'];
$signatureMoves = ['hadouken', 'shoryuken', 'spinning bird kick', 'sonic boom'];

foreach (Multi::zip($names, $countries, $signatureMoves) as [$name, $country, $signatureMove]) {
    $streetFighter = new StreetFighter($name, $country, $signatureMove);
}


use IterTools\Multi;

$letters = ['A', 'B', 'C'];
$numbers = [1, 2, 3];

foreach (Multi::zipEqual($letters, $numbers) as [$letter, $number]) {
    // ['A', 1], ['B', 2], ['C', 3]
}


use IterTools\Multi;

$default = '?';
$letters = ['A', 'B'];
$numbers = [1, 2, 3];

foreach (Multi::zipFilled($default, $letters, $numbers) as [$letter, $number]) {
    // ['A', 1], ['B', 2], ['?', 3]
}


use IterTools\Multi;

$letters = ['A', 'B', 'C'];
$numbers = [1, 2];

foreach (Multi::zipLongest($letters, $numbers) as [$letter, $number]) {
    // ['A', 1], ['B', 2], ['C', null]
}


use IterTools\Single;

$movies = [
    'Phantom Menace', 'Attack of the Clones', 'Revenge of the Sith',
    'A New Hope', 'Empire Strikes Back', 'Return of the Jedi',
    'The Force Awakens', 'The Last Jedi', 'The Rise of Skywalker'
];

foreach (Single::chunkwise($movies, 3) as $trilogy) {
    $trilogies[] = $trilogy;
}
// [
//     ['Phantom Menace', 'Attack of the Clones', 'Revenge of the Sith'],
//     ['A New Hope', 'Empire Strikes Back', 'Return of the Jedi'],
//     ['The Force Awakens', 'The Last Jedi', 'The Rise of Skywalker]'
// ]


use IterTools\Single;

$numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];

foreach (Single::chunkwiseOverlap($numbers, 3, 1) as $chunk) {
    // [1, 2, 3], [3, 4, 5], [5, 6, 7], [7, 8, 9], [9, 10]
}


use IterTools\Single;

$movies = [
    'Phantom Menace', 'Attack of the Clones', 'Revenge of the Sith',
    'A New Hope', 'Empire Strikes Back', 'Return of the Jedi',
    'The Force Awakens', 'The Last Jedi', 'The Rise of Skywalker'
];
$goodMovies = [0, 0, 0, 1, 1, 1, 1, 0, 0];

foreach (Single::compress($movies, $goodMovies) as $goodMovie) {
    print($goodMovie);
}
// 'A New Hope', 'Empire Strikes Back', 'Return of the Jedi', 'The Force Awakens'


use IterTools\Single;

$starWarsEpisodes = [
    'I'    => 'The Phantom Menace',
    'II'   => 'Attack of the Clones',
    'III'  => 'Revenge of the Sith',
    'IV'   => 'A New Hope',
    'V'    => 'The Empire Strikes Back',
    'VI'   => 'Return of the Jedi',
    'VII'  => 'The Force Awakens',
    'VIII' => 'The Last Jedi',
    'IX'   => 'The Rise of Skywalker',
];
$originalTrilogyNumbers = ['IV', 'V', 'VI'];

foreach (Single::compressAssociative($starWarsEpisodes, $originalTrilogyNumbers) as $episode => $title) {
    print("$episode: $title" . \PHP_EOL);
}
// IV: A New Hope
// V: The Empire Strikes Back
// VI: Return of the Jedi


use IterTools\Single;

$scores    = [50, 60, 70, 85, 65, 90];
$predicate = fn ($x) => $x < 70;

foreach (Single::dropWhile($scores, $predicate) as $score) {
    print($score);
}
// 70, 85, 65, 90


use IterTools\Single;

$starWarsEpisodes   = [1, 2, 3, 4, 5, 6, 7, 8, 9];
$goodMoviePredicate = fn ($episode) => $episode > 3 && $episode < 8;

foreach (Single::filter($starWarsEpisodes, $goodMoviePredicate) as $goodMovie) {
    print($goodMovie);
}
// 4, 5, 6, 7


use IterTools\Single;

$reportCardGrades = [100, 0, 95, 85, 0, 94, 0];

foreach (Single::filterTrue($reportCardGrades) as $goodGrade) {
    print($goodGrade);
}
// 100, 95, 85, 94


use IterTools\Single;

$alerts = [0, 1, 1, 0, 1, 0, 0, 1, 1];

foreach (Single::filterFalse($alerts) as $noAlert) {
    print($noAlert);
}
// 0, 0, 0, 0


use IterTools\Single;

$olympics = [
    2000 => 'Sydney',
    2002 => 'Salt Lake City',
    2004 => 'Athens',
    2006 => 'Turin',
    2008 => 'Beijing',
    2010 => 'Vancouver',
    2012 => 'London',
    2014 => 'Sochi',
    2016 => 'Rio de Janeiro',
    2018 => 'Pyeongchang',
    2020 => 'Tokyo',
    2022 => 'Beijing',
];

$summerFilter = fn ($year) => $year % 4 === 0;

foreach (Single::filterKeys($olympics, $summerFilter) as $year => $hostCity) {
    print("$year: $hostCity" . \PHP_EOL);
}
// 2000: Sydney
// 2004: Athens
// 2008: Beijing
// 2012: London
// 2016: Rio de Janeiro
// 2020: Tokyo


use IterTools\Single;

$data   = [1, 2, 3, 4, 5];
$mapper = fn ($item) => [$item, -$item];

foreach (Single::flatMap($data, $mapper) as $number) {
    print($number . ' ');
}
// 1 -1 2 -2 3 -3 4 -4 5 -5


use IterTools\Single;

$multidimensional = [1, [2, 3], [4, 5]];

$flattened = [];
foreach (Single::flatten($multidimensional) as $number) {
    $flattened[] = $number;
}
// [1, 2, 3, 4, 5]


use IterTools\Single;

$cartoonCharacters = [
    ['Garfield', 'cat'],
    ['Tom', 'cat'],
    ['Felix', 'cat'],
    ['Heathcliff', 'cat'],
    ['Snoopy', 'dog'],
    ['Scooby-Doo', 'dog'],
    ['Odie', 'dog'],
    ['Donald', 'duck'],
    ['Daffy', 'duck'],
];

$charactersGroupedByAnimal = [];
foreach (Single::groupBy($cartoonCharacters, fn ($x) => $x[1]) as $animal => $characters) {
    $charactersGroupedByAnimal[$animal] = $characters;
}
/*
'cat' => [
    ['Garfield', 'cat'],
    ['Tom', 'cat'],
    ['Felix', 'cat'],
    ['Heathcliff', 'cat'],
],
'dog' => [
    ['Snoopy', 'dog'],
    ['Scooby-Doo', 'dog'],
    ['Odie', 'dog'],
],
'duck' => [
    ['Donald', 'duck'],
    ['Daffy', 'duck'],
*/


use IterTools\Single;

$matrixMovies = ['The Matrix', 'The Matrix Reloaded', 'The Matrix Revolutions', 'The Matrix Resurrections'];
$limit        = 1;

foreach (Single::limit($matrixMovies, $limit) as $goodMovie) {
    print($goodMovie);
}
// 'The Matrix' (and nothing else)


use IterTools\Single;

$grades               = [100, 99, 95, 98, 100];
$strictParentsOpinion = fn ($g) => $g === 100 ? 'A' : 'F';

foreach (Single::map($grades, $strictParentsOpinion) as $actualGrade) {
    print($actualGrade);
}
// A, F, F, F, A


use IterTools\Single;

$friends = ['Ross', 'Rachel', 'Chandler', 'Monica', 'Joey', 'Phoebe'];

foreach (Single::pairwise($friends) as [$leftFriend, $rightFriend]) {
    print("{$leftFriend} and {$rightFriend}");
}
// Ross and Rachel, Rachel and Chandler, Chandler and Monica, ...


use IterTools\Single;

$data        = 'Beetlejuice';
$repetitions = 3;

foreach (Single::repeat($data, $repetitions) as $repeated) {
    print($repeated);
}
// 'Beetlejuice', 'Beetlejuice', 'Beetlejuice'


use IterTools\Single;

$data = [
    [
        'title'   => 'Star Wars: Episode IV – A New Hope',
        'episode' => 'IV',
        'year'    => 1977,
    ],
    [
        'title'   => 'Star Wars: Episode V – The Empire Strikes Back',
        'episode' => 'V',
        'year'    => 1980,
    ],
    [
        'title' => 'Star Wars: Episode VI – Return of the Jedi',
        'episode' => 'VI',
        'year' => 1983,
    ],
];
$reindexFunc = fn (array $swFilm) => $swFilm['episode'];

$reindexedData = [];
foreach (Single::reindex($data, $reindexFunc) as $key => $filmData) {
    $reindexedData[$key] = $filmData;
}
// [
//     'IV' => [
//         'title'   => 'Star Wars: Episode IV – A New Hope',
//         'episode' => 'IV',
//         'year'    => 1977,
//     ],
//     'V' => [
//         'title'   => 'Star Wars: Episode V – The Empire Strikes Back',
//         'episode' => 'V',
//         'year'    => 1980,
//     ],
//     'VI' => [
//         'title' => 'Star Wars: Episode VI – Return of the Jedi',
//         'episode' => 'VI',
//         'year' => 1983,
//     ],
// ]


use IterTools\Single;

$words = ['Alice', 'answers', 'your', 'questions', 'Bob'];

foreach (Single::reverse($words) as $word) {
    print($word . ' ');
}
// Bob questions your answers Alice


use IterTools\Single;

$movies = [
    'The Phantom Menace', 'Attack of the Clones', 'Revenge of the Sith',
    'A New Hope', 'The Empire Strikes Back', 'Return of the Jedi',
    'The Force Awakens', 'The Last Jedi', 'The Rise of Skywalker'
];

$prequelsRemoved = [];
foreach (Single::skip($movies, 3) as $nonPrequel) {
    $prequelsRemoved[] = $nonPrequel;
} // Episodes IV - IX

$onlyTheBest = [];
foreach (Single::skip($prequelsRemoved, 3, 3) as $nonSequel) {
    $onlyTheBest[] = $nonSequel;
}
// 'A New Hope', 'The Empire Strikes Back', 'Return of the Jedi'


use IterTools\Single;

$olympics = [1992, 1994, 1996, 1998, 2000, 2002, 2004, 2006, 2008, 2010, 2012, 2014, 2016, 2018, 2020, 2022];
$winterOlympics = [];

foreach (Single::slice($olympics, 1, 8, 2) as $winterYear) {
    $winterOlympics[] = $winterYear;
}
// [1994, 1998, 2002, 2006, 2010, 2014, 2018, 2022]


use IterTools\Single;

$string = 'MickeyMouse';

$listOfCharacters = [];
foreach (Single::string($string) as $character) {
    $listOfCharacters[] = $character;
}
// ['M', 'i', 'c', 'k', 'e', 'y', 'M', 'o', 'u', 's', 'e']


use IterTools\Single;

$prices = [0, 0, 5, 10, 0, 0, 9];
$isFree = fn ($price) => $price == 0;

foreach (Single::takeWhile($prices, $isFree) as $freePrice) {
    print($freePrice);
}
// 0, 0


use IterTools\Infinite;

$start = 1;
$step  = 1;

foreach (Infinite::count($start, $step) as $i) {
    print($i);
}
// 1, 2, 3, 4, 5 ...


use IterTools\Infinite;

$hands = ['rock', 'paper', 'scissors'];

foreach (Infinite::cycle($hands) as $hand) {
    RockPaperScissors::playHand($hand);
}
// rock, paper, scissors, rock, paper, scissors, ...


use IterTools\Infinite;

$dialogue = 'Are we there yet?';

foreach (Infinite::repeat($dialogue) as $repeated) {
    print($repeated);
}
// 'Are we there yet?', 'Are we there yet?', 'Are we there yet?', ...


use IterTools\Random;

$cards       = ['Ace', 'King', 'Queen', 'Jack', 'Joker'];
$repetitions = 10;

foreach (Random::choice($cards, $repetitions) as $card) {
    print($card);
}
// 'King', 'Jack', 'King', 'Ace', ... [random]


use IterTools\Random;

$repetitions = 10;

foreach (Random::coinFlip($repetitions) as $coinFlip) {
    print($coinFlip);
}
// 1, 0, 1, 1, 0, ... [random]


use IterTools\Random;

$min         = 1;
$max         = 4;
$repetitions = 10;

foreach (Random::number($min, $max, $repetitions) as $number) {
    print($number);
}
// 3, 2, 5, 5, 1, 2, ... [random]


use IterTools\Random;

$repetitions = 10;

foreach (Random::percentage($repetitions) as $percentage) {
    print($percentage);
}
// 0.30205562629132, 0.59648594775233, ... [random]


use IterTools\Random;

$repetitions = 10;

foreach (Random::rockPaperScissors($repetitions) as $rpsHand) {
    print($rpsHand);
}
// 'paper', 'rock', 'rock', 'scissors', ... [random]


use IterTools\Math;

$grades = ['A', 'A', 'B', 'B', 'B', 'C'];

foreach (Math::frequencies($grades) as $grade => $frequency) {
    print("$grade: $frequency" . \PHP_EOL);
}
// A: 2, B: 3, C: 1


use IterTools\Math;

$grades = ['A', 'A', 'B', 'B', 'B', 'C'];

foreach (Math::relativeFrequencies($grades) as $grade => $frequency) {
    print("$grade: $frequency" . \PHP_EOL);
}
// A: 0.33, B: 0.5, C: 0.166


use IterTools\Math;

$grades = [100, 80, 80, 90, 85];

foreach (Math::runningAverage($grades) as $runningAverage) {
    print($runningAverage);
}
// 100, 90, 86.667, 87.5, 87


use IterTools\Math;

$credits = [1, 2, 3, 4, 5];

foreach (Math::runningDifference($credits) as $runningDifference) {
    print($runningDifference);
}
// -1, -3, -6, -10, -15


use IterTools\Math;

$dartsScores   = [50, 50, 25, 50];
$startingScore = 501;

foreach (Math::runningDifference($dartsScores, $startingScore) as $runningScore) {
    print($runningScore);
}
// 501, 451, 401, 376, 326


use IterTools\Math;

$numbers = [1, 2, 1, 3, 5];

foreach (Math::runningMax($numbers) as $runningMax) {
    print($runningMax);
}
// 1, 2, 2, 3, 5


use IterTools\Math;

$numbers = [3, 4, 2, 5, 1];

foreach (Math::runningMin($numbers) as $runningMin) {
    print($runningMin);
}
// 3, 3, 2, 2, 1


use IterTools\Math;

$numbers = [1, 2, 3, 4, 5];

foreach (Math::runningProduct($numbers) as $runningProduct) {
    print($runningProduct);
}
// 1, 2, 6, 24, 120


use IterTools\Math;

$numbers      = [1, 2, 3, 4, 5];
$initialValue = 5;

foreach (Math::runningProduct($numbers, $initialValue) as $runningProduct) {
    print($runningProduct);
}
// 5, 5, 10, 30, 120, 600


use IterTools\Math;

$prices = [1, 2, 3, 4, 5];

foreach (Math::runningTotal($prices) as $runningTotal) {
    print($runningTotal);
}
// 1, 3, 6, 10, 15


use IterTools\Math;

$prices       = [1, 2, 3, 4, 5];
$initialValue = 5;

foreach (Math::runningTotal($prices, $initialValue) as $runningTotal) {
    print($runningTotal);
}
// 5, 6, 8, 11, 15, 20


use IterTools\Set;

$chessSet = ['rook', 'rook', 'knight', 'knight', 'bishop', 'bishop', 'king', 'queen', 'pawn', 'pawn', ... ];

foreach (Set::distinct($chessSet) as $chessPiece) {
    print($chessPiece);
}
// rook, knight, bishop, king, queen, pawn

$mixedTypes = [1, '1', 2, '2', 3];

foreach (Set::distinct($mixedTypes, false) as $datum) {
    print($datum);
}
// 1, 2, 3


use IterTools\Set;

$streetFighterConsoleReleases = [
    ['id' => '112233', 'name' => 'Street Fighter 3 3rd Strike', 'console' => 'Dreamcast'],
    ['id' => '223344', 'name' => 'Street Fighter 3 3rd Strike', 'console' => 'PS4'],
    ['id' => '334455', 'name' => 'Street Fighter 3 3rd Strike', 'console' => 'PS5'],
    ['id' => '445566', 'name' => 'Street Fighter VI', 'console' => 'PS4'],
    ['id' => '556677', 'name' => 'Street Fighter VI', 'console' => 'PS5'],
    ['id' => '667788', 'name' => 'Street Fighter VI', 'console' => 'PC'],
];
$compareBy = fn ($sfTitle) => $sfTitle['name'];

$uniqueTitles = [];
foreach (Set::distinctBy($streetFighterConsoleReleases, $compareBy) as $sfTitle) {
    $uniqueTitles[] = $sfTitle;
}

// Contains one SF3 3rd Strike entry and one SFVI entry.


use IterTools\Set;

$chessPieces = ['rook', 'knight', 'bishop', 'queen', 'king', 'pawn'];
$shogiPieces = ['rook', 'knight', 'bishop' 'king', 'pawn', 'lance', 'gold general', 'silver general'];

foreach (Set::intersection($chessPieces, $shogiPieces) as $commonPiece) {
    print($commonPiece);
}
// rook, knight, bishop, king, pawn


use IterTools\Set;

$numbers  = [1, 2, 3, 4, 5];
$numerics = ['1', '2', 3];

foreach (Set::intersectionCoercive($numbers, $numerics) as $commonNumber) {
    print($commonNumber);
}
// 1, 2, 3


use IterTools\Set;

$staticallyTyped    = ['c++', 'java', 'c#', 'go', 'haskell'];
$dynamicallyTyped   = ['php', 'python', 'javascript', 'typescript'];
$supportsInterfaces = ['php', 'java', 'c#', 'typescript'];

foreach (Set::partialIntersection(2, $staticallyTyped, $dynamicallyTyped, $supportsInterfaces) as $language) {
    print($language);
}
// c++, java, c#, go, php


use IterTools\Set;

$set1 = [1, 2, 3],
$set2 = ['2', '3', 4, 5],
$set3 = [1, '2'],

foreach (Set::partialIntersectionCoercive(2, $set1, $set2, $set3) as $partiallyCommonNumber) {
    print($partiallyCommonNumber);
}
// 1, 2, 3


use IterTools\Set;

$a = [1, 2, 3, 4, 7];
$b = ['1', 2, 3, 5, 8];
$c = [1, 2, 3, 6, 9];

foreach (Set::symmetricDifference($a, $b, $c) as $item) {
    print($item);
}
// 1, 4, 5, 6, 7, 8, 9


use IterTools\Set;

$a = [1, 2, 3, 4, 7];
$b = ['1', 2, 3, 5, 8];
$c = [1, 2, 3, 6, 9];

foreach (Set::symmetricDifferenceCoercive($a, $b, $c) as $item) {
    print($item);
}
// 4, 5, 6, 7, 8, 9


use IterTools\Set;

$a = [1, 2, 3];
$b = [3, 4];
$c = [1, 2, 3, 6, 7];

foreach (Set::union($a, $b, $c) as $item) {
    print($item);
}
//1, 2, 3, 4, 6, 7


use IterTools\Set;

$a = ['1', 2, 3];
$b = [3, 4];
$c = [1, 2, 3, 6, 7];

foreach (Set::unionCoercive($a, $b, $c) as $item) {
    print($item);
}
//1, 2, 3, 4, 6, 7


use IterTools\Single;

$worldPopulations = [
    'China'     => 1_439_323_776,
    'India'     => 1_380_004_385,
    'Indonesia' => 273_523_615,
    'Pakistan'  => 220_892_340,
    'USA'       => 331_002_651,
];

foreach (Sort::sort($worldPopulations) as $country => $population) {
    print("$country: $population" . \PHP_EOL);
}
// Pakistan: 220,892,340
// Indonesia: 273,523,615
// USA: 331,002,651
// India: 1,380,004,385
// China: 1,439,323,776


use IterTools\Single;

$data = [3, 4, 5, 9, 8, 7, 1, 6, 2];

foreach (Sort::sort($data) as $datum) {
    print($datum);
}
// 1, 2, 3, 4, 5, 6, 7, 8, 9


use IterTools\File;

$fileHandle = \fopen('path/to/file.csv', 'r');

foreach (File::readCsv($fileHandle) as $row) {
    print_r($row);
}
// Each column field is an element of the array


use IterTools\File;

$fileHandle = \fopen('path/to/file.txt', 'r');

foreach (File::readLines($fileHandle) as $line) {
    print($line);
}


use IterTools\Transform;

$daysOfWeek = ['Mon', 'Tues', 'Wed', 'Thurs', 'Fri', 'Sat', 'Sun'];
$count = 3;

[$week1, $week2, $week3] = Transform::tee($data, $count);
// Each $week contains iterator containing ['Mon', 'Tues', 'Wed', 'Thurs', 'Fri', 'Sat', 'Sun']


use IterTools\Transform;

$iterator = new \ArrayIterator([1, 2, 3, 4, 5]);

$array = Transform::toArray($iterator);


use IterTools\Transform;

$messages = ['message 1', 'message 2', 'message 3'];

$keyFunc   = fn ($msg) => \md5($msg);
$valueFunc = fn ($msg) => strtoupper($msg);

$associativeArray = Transform::toAssociativeArray($messages, $keyFunc, $valueFunc);
// [
//     '1db65a6a0a818fd39655b95e33ada11d' => 'MESSAGE 1',
//     '83b2330607fe8f817ce6d24249dea373' => 'MESSAGE 2',
//     '037805d3ad7b10c5b8425427b516b5ce' => 'MESSAGE 3',
// ]


use IterTools\Transform;

$array = [1, 2, 3, 4, 5];

$iterator = Transform::toIterator($array);


use IterTools\Summary;

$finalFantasyNumbers = [4, 5, 6];
$isOnSuperNintendo   = fn ($ff) => $ff >= 4 && $ff <= 6;

$boolean = Summary::allMatch($finalFantasyNumbers, $isOnSuperNintendo);
// true

$isOnPlaystation = fn ($ff) => $ff >= 7 && $ff <= 9;

$boolean = Summary::allMatch($finalFantasyNumbers, $isOnPlaystation);
// false


use IterTools\Summary;

$items = ['fingerprints', 'snowflakes', 'eyes', 'DNA']

$boolean = Summary::allUnique($items);
// true


use IterTools\Summary;

$answers          = ['fish', 'towel', 42, "don't panic"];
$isUltimateAnswer = fn ($a) => a == 42;

$boolean = Summary::anyMatch($answers, $isUltimateAnswer);
// true


use IterTools\Summary;

$iter = ['i', 't', 'e', 'r'];
$rite = ['r', 'i', 't', 'e'];
$reit = ['r', 'e', 'i', 't'];
$tier = ['t', 'i', 'e', 'r'];
$tire = ['t', 'i', 'r', 'e'];
$trie = ['t', 'r', 'i', 'e'];

$boolean = Summary::arePermutations($iter, $rite, $reit, $tier, $tire, $trie);
// true


use IterTools\Summary;

$set1 = [1, 2.0, '3'];
$set2 = [2.0, '1', 3];
$set3 = [3, 2, 1];

$boolean = Summary::arePermutationsCoercive($set1, $set2, $set3);
// true


use IterTools\Summary;

$twoTruthsAndALie = [true, true, false];
$n                = 2;

$boolean = Summary::exactlyN($twoTruthsAndALie, $n);
// true

$ages      = [18, 21, 24, 54];
$n         = 4;
$predicate = fn ($age) => $age >= 21;

$boolean = Summary::exactlyN($ages, $n, $predicate);
// false


use IterTools\Summary;

$data = []

$boolean = Summary::isEmpty($data);
// true


use IterTools\Summary;

$numbers          = [0, 2, 4, 1, 3, 5];
$evensBeforeOdds = fn ($item) => $item % 2 === 0;

$boolean = Summary::isPartitioned($numbers, $evensBeforeOdds);


use IterTools\Summary;

$numbers = [1, 2, 3, 4, 5];

$boolean = Summary::isSorted($numbers);
// true

$numbers = [3, 2, 3, 4, 5];

$boolean = Summary::isSorted($numbers);
// false


use IterTools\Summary;

$numbers = [5, 4, 3, 2, 1];

$boolean = Summary::isReversed($numbers);
// true

$numbers = [1, 4, 3, 2, 1];

$boolean = Summary::isReversed($numbers);
// false


use IterTools\Summary;

$grades         = [45, 50, 61, 0];
$isPassingGrade = fn ($grade) => $grade >= 70;

$boolean = Summary::noneMatch($grades, $isPassingGrade);
// true


use IterTools\Summary;

$cocaColaIngredients = ['carbonated water', 'sugar', 'caramel color', 'phosphoric acid'];
$pepsiIngredients    = ['carbonated water', 'sugar', 'caramel color', 'phosphoric acid'];

$boolean = Summary::same($cocaColaIngredients, $pepsiIngredients);
// true

$cocaColaIngredients = ['carbonated water', 'sugar', 'caramel color', 'phosphoric acid'];
$spriteIngredients   = ['carbonated water', 'sugar', 'citric acid', 'lemon lime flavorings'];

$boolean = Summary::same($cocaColaIngredients, $spriteIngredients);
// false


use IterTools\Summary;

$prequels  = ['Phantom Menace', 'Attack of the Clones', 'Revenge of the Sith'];
$originals = ['A New Hope', 'Empire Strikes Back', 'Return of the Jedi'];
$sequels   = ['The Force Awakens', 'The Last Jedi', 'The Rise of Skywalker'];

$boolean = Summary::sameCount($prequels, $originals, $sequels);
// true

$batmanMovies = ['Batman Begins', 'The Dark Knight', 'The Dark Knight Rises'];
$matrixMovies = ['The Matrix', 'The Matrix Reloaded', 'The Matrix Revolutions', 'The Matrix Resurrections'];

$result = Summary::sameCount($batmanMovies, $matrixMovies);
// false


use IterTools\Reduce;

$grades = [100, 90, 95, 85, 94];

$finalGrade = Reduce::toAverage($numbers);
// 92.8


use IterTools\Reduce;

$someIterable = ImportantThing::getCollectionAsIterable();

$length = Reduce::toCount($someIterable);
// 3


use IterTools\Reduce;

$medals = ['gold', 'silver', 'bronze'];

$first = Reduce::toFirst($medals);
// gold


use IterTools\Reduce;

$weekdays = ['Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday'];

$firstAndLast = Reduce::toFirstAndLast($weekdays);
// [Monday, Friday]


use IterTools\Reduce;

$gnomesThreePhasePlan = ['Collect underpants', '?', 'Profit'];

$lastPhase = Reduce::toLast($gnomesThreePhasePlan);
// Profit


use IterTools\Reduce;

$numbers = [5, 3, 1, 2, 4];

$result = Reduce::toMax($numbers);
// 5

$movieRatings = [
    [
        'title' => 'Star Wars: Episode IV - A New Hope',
        'rating' => 4.6
    ],
    [
        'title' => 'Star Wars: Episode V - The Empire Strikes Back',
        'rating' => 4.8
    ],
    [
        'title' => 'Star Wars: Episode VI - Return of the Jedi',
        'rating' => 4.6
    ],
];
$compareBy = fn ($movie) => $movie['rating'];

$highestRatedMovie = Reduce::toMax($movieRatings, $compareBy);
// [
//     'title' => 'Star Wars: Episode V - The Empire Strikes Back',
//     'rating' => 4.8
// ];


use IterTools\Reduce;

$numbers = [5, 3, 1, 2, 4];

$result = Reduce::toMin($numbers);
// 1


$movieRatings = [
    [
        'title' => 'The Matrix',
        'rating' => 4.7
    ],
    [
        'title' => 'The Matrix Reloaded',
        'rating' => 4.3
    ],
    [
        'title' => 'The Matrix Revolutions',
        'rating' => 3.9
    ],
    [
        'title' => 'The Matrix Resurrections',
        'rating' => 2.5
    ],
];
$compareBy = fn ($movie) => $movie['rating'];

$lowestRatedMovie = Reduce::toMin($movieRatings, $compareBy);
// [
//     'title' => 'The Matrix Resurrections',
//     'rating' => 2.5
// ]


use IterTools\Reduce;

$numbers = [1, 2, 7, -1, -2, -3];

[$min, $max] = Reduce::toMinMax($numbers);
// [-3, 7]

$reportCard = [
    [
        'subject' => 'history',
        'grade' => 90
    ],
    [
        'subject' => 'math',
        'grade' => 98
    ],
    [
        'subject' => 'science',
        'grade' => 92
    ],
    [
        'subject' => 'english',
        'grade' => 85
    ],
    [
        'subject' => 'programming',
        'grade' => 100
    ],
];
$compareBy = fn ($class) => $class['grade'];

$bestAndWorstSubject = Reduce::toMinMax($reportCard, $compareBy);
// [
//     [
//         'subject' => 'english',
//         'grade' => 85
//     ],
//     [
//         'subject' => 'programming',
//         'grade' => 100
//     ],
// ]


use IterTools\Reduce;

$lotrMovies = ['The Fellowship of the Ring', 'The Two Towers', 'The Return of the King'];

$rotk = Reduce::toNth($lotrMovies, 2);
// 20


use IterTools\Reduce;

$primeFactors = [5, 2, 2];

$number = Reduce::toProduct($primeFactors);
// 20


use IterTools\Reduce;

$sfWakeupOptions = ['mid', 'low', 'overhead', 'throw', 'meaty'];

$wakeupOption = Reduce::toRandomValue($sfWakeupOptions);
// e.g., throw


use IterTools\Reduce;

$grades = [100, 90, 80, 85, 95];

$range = Reduce::toRange($numbers);
// 20


use IterTools\Reduce;

$words = ['IterTools', 'PHP', 'v1.0'];

$string = Reduce::toString($words);
// IterToolsPHPv1.0
$string = Reduce::toString($words, '-');
// IterTools-PHP-v1.0
$string = Reduce::toString($words, '-', 'Library: ');
// Library: IterTools-PHP-v1.0
$string = Reduce::toString($words, '-', 'Library: ', '!');
// Library: IterTools-PHP-v1.0!


use IterTools\Reduce;

$parts = [10, 20, 30];

$sum = Reduce::toSum($parts);
// 60


use IterTools\Reduce;

$input = [1, 2, 3, 4, 5];
$sum   = fn ($carry, $item) => $carry + $item;

$result = Reduce::toValue($input, $sum, 0);
// 15


   $result = Stream::of([1, 1, 2, 2, 3, 4, 5])
      ->distinct()                  // [1, 2, 3, 4, 5]
      ->map(fn ($x) => $x**2)       // [1, 4, 9, 16, 25]
      ->filter(fn ($x) => $x < 10)  // [1, 4, 9]
      ->toSum();                    // 14


   $result = Stream::of([1, 1, 2, 2, 3, 4, 5])
      ->distinct()                  // [1, 2, 3, 4, 5]
      ->map(fn ($x) => $x**2)       // [1, 4, 9, 16, 25]
      ->filter(fn ($x) => $x < 10); // [1, 4, 9]

   foreach ($result as $item) {
       // 1, 4, 9
   }


use IterTools\Stream;

$iterable = [1, 2, 3];

$result = Stream::of($iterable)
    ->chainWith([4, 5, 6], [7, 8, 9])
    ->zipEqualWith([1, 2, 3, 4, 5, 6, 7, 8, 9])
    ->toValue(fn ($carry, $item) => $carry + array_sum($item));
// 90


use IterTools\Stream;

$result = Stream::ofCoinFlips(10)
    ->filterTrue()
    ->toCount();
// 5 (random)

json
{
  "arkrogoyski/itertools-php": "1.*"
  }
}

bash
$ php composer.phar install


$ php composer.phar

Single::chunkwise(iterable $data, int $chunkSize)

Single::filter(iterable $data, callable $predicate)

Single::groupBy(iterable $data, callable $groupKeyFunction, callable $itemKeyFunction = null)

Single::limit(iterable $data, int $limit)

Single::skip(iterable $data, int $count, int $offset = 0)

Single::slice(iterable $data, int $start = 0, int $count = null, int $step = 1)

Sort::sort(iterable $data, callable $comparator = null)

Sort::sort(iterable $data, callable $comparator = null)

Transform::tee(iterable $data, int $count): array

Transform::toArray(iterable $data): array

Transform::toAssociativeArray(iterable $data, callable $keyFunc = null, callable $valueFunc = null): array

Transform::toArray(iterable $data): array

Reduce::toFirstAndLast(iterable $data): array{mixed, mixed}

Reduce::toMax(iterable $data, callable $compareBy = null): mixed|null

Reduce::toMin(iterable $data, callable $compareBy = null): mixed|null

Reduce::toMinMax(iterable $numbers, callable $compareBy = null): array

php
use IterTools\Stream;

$fileHandle = \fopen('path/to/file.csv', 'r');

$result = Stream::of($fileHandle)
    ->toArray();

php
use IterTools\Stream;

$fileHandle = \fopen('path/to/file.txt', 'r');

$result = Stream::of($fileHandle)
    ->map('strtoupper');
    ->toArray();