mapReduce

mapper.php
reducer.php

#!/usr/local/bin/php

<?php

$word2count = array();

// input comes from STDIN (standard input)

// You can this code :$stdin = fopen(“php://stdin”, “r”);

while (($line = fgets(STDIN)) !== false) {

// remove leading and trailing whitespace and lowercase

$line = strtolower(trim($line));

// split the line into words while removing any empty string

$words = preg_split(‘/\W/’, $line, 0, PREG_SPLIT_NO_EMPTY);

// increase counters

foreach ($words as $word) {

$word2count[$word] += 1;

}

}

// write the results to STDOUT (standard output)

// what we output here will be the input for the

// Reduce step, i.e. the input for reducer.py

foreach ($word2count as $word => $count) {

// tab-delimited

echo $word, chr(9), $count, PHP_EOL;

}

?>

#!/usr/local/bin/php

<?php

$word2count = array();

// input comes from STDIN

while (($line = fgets(STDIN)) !== false) {

// remove leading and trailing whitespace

$line = trim($line);

// parse the input we got from mapper.php

list($word, $count) = explode(chr(9), $line);

// convert count (currently a string) to int

$count = intval($count);

// sum counts

if ($count > 0) $word2count[$word] += $count;

}

// sort the words lexigraphically

//

// this set is NOT required, we just do it so that our

// final output will look more like the official Hadoop

// word count examples

ksort($word2count);

// write the results to STDOUT (standard output)

foreach ($word2count as $word => $count) {

echo $word, chr(9), $count, PHP_EOL;

}

?>