PHP code example of jotaelesalinas / php-mapreduce

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

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

    

jotaelesalinas / php-mapreduce example snippets

$source = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
$mapper = fn($item) => $item * 2;
$reducer = fn($carry, $item) => ($carry ?? 0) + $item;

$result = MapReduce\MapReduce::create()
    ->setInput($source)
    ->setMapper($mapper)
    ->setReducer($reducer)
    ->run();

print_r($result);

$odd_numbers = fn($item) => $item % 2 === 0;
$greater_than_10 = fn($item) => $item > 10;

$result = MapReduce\MapReduce::create([
        "input" => $source, 
        "mapper" => $mapper, 
        "reducer" => $reducer, 
    ])
    // only odd numbers are passed to the mapper function
    ->setPreFilter($odd_numbers)
    // only numbers greater than 10 are passed to the reducer function
    ->setPostFilter($greater_than_10)
    ->run();

print_r($result);

$source = [
    [ "first_name" => "Susanna", "last_name" => "Connor",  "member" => "y", "age" => 20],
    [ "first_name" => "Adrian",  "last_name" => "Smith",   "member" => "n", "age" => 22],
    [ "first_name" => "Mike",    "last_name" => "Mendoza", "member" => "n", "age" => 24],
    [ "first_name" => "Linda",   "last_name" => "Duguin",  "member" => "y", "age" => 26],
    [ "first_name" => "Bob",     "last_name" => "Svenson", "member" => "n", "age" => 28],
    [ "first_name" => "Nancy",   "last_name" => "Potier",  "member" => "y", "age" => 30],
    [ "first_name" => "Pete",    "last_name" => "Adams",   "member" => "n", "age" => 32],
    [ "first_name" => "Susana",  "last_name" => "Zommers", "member" => "y", "age" => 34],
    [ "first_name" => "Adrian",  "last_name" => "Deville", "member" => "n", "age" => 36],
    [ "first_name" => "Mike",    "last_name" => "Cole",    "member" => "n", "age" => 38],
    [ "first_name" => "Mike",    "last_name" => "Angus",   "member" => "n", "age" => 40],
];

// mapper does nothing
$mapper = fn($x) => $x;

// number of persons and sum of ages
$reduceAgeSum = function ($carry, $item) {
    if (is_null($carry)) {
        return [
            'count' => 1,
            'age_sum' => $item['age'],
        ];
    }
    
    $count = $carry['count'] + 1;
    $age_sum = $carry['age_sum'] + $item['age'];
    
    return compact('count', 'age_sum');
};

$result = MapReduce\MapReduce::create([
        "input" => $source, 
        "mapper" => $mapper, 
        "reducer" => $reduceAgeSum, 
    ])
    // group by field 'member'
    ->setGroupBy('member')
    ->run();

print_r($result);

$closestTen = fn($x) => floor($x['age'] / 10) * 10;

$result = MapReduce\MapReduce::create([
        "input" => $source, 
        "mapper" => $mapper, 
        "reducer" => $reduceAgeSum, 
    ])
    // group by age ranges of 10
    ->setGroupBy($closestTen)
    ->run();

print_r($result);

$result = MapReduce\MapReduce::create([
        "mapper" => $mapper, 
        "reducer" => $reducer, 
    ])
    ->setInput(csvReadGenerator('myfile.csv'))
    ->run();

$result = MapReduce\MapReduce::create([
        "mapper" => $mapper, 
        "reducer" => $reducer, 
    ])
    ->setInput($arrayData, csvReadGenerator('myfile.csv'))
    ->run();

$result = MapReduce\MapReduce::create([
        "mapper" => $mapper, 
        "reducer" => $reducer, 
    ])
    ->setOutput(csvWriteGenerator('results.csv'))
    ->run();

$result = MapReduce\MapReduce::create([
        "mapper" => $mapper, 
        "reducer" => $reducer, 
    ])
    ->setOutput(csvWriteGenerator('results.csv'), consoleGenerator())
    ->run();

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