Inverted index: Difference between revisions
Content added Content deleted
SqrtNegInf (talk | contribs) m (→{{header|Perl 6}}: fixed my typo) |
(added simple PHP version) |
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say "$word => {%inv.{$word.lc}//'(not found)'}";
}
}
}</lang>
=={{header|PHP}}==
<lang php><?php
function buildInvertedIndex($filenames)
{
$invertedIndex = [];
foreach($filenames as $filename)
{
$data = file_get_contents($filename);
if($data === false) die('Unable to read file: ' . $filename);
preg_match_all('/(\w+)/', $data, $matches, PREG_SET_ORDER);
foreach($matches as $match)
{
$word = strtolower($match[0]);
if(!array_key_exists($word, $invertedIndex)) $invertedIndex[$word] = [];
if(!in_array($filename, $invertedIndex[$word], true)) $invertedIndex[$word][] = $filename;
}
}
return $invertedIndex;
}
function lookupWord($invertedIndex, $word)
{
return array_key_exists($word, $invertedIndex) ? $invertedIndex[$word] : false;
}
$invertedIndex = buildInvertedIndex2(['file1.txt', 'file2.txt', 'file3.txt']);
foreach(['cat', 'is', 'banana', 'it'] as $word)
{
$matches = lookupWord($invertedIndex, $word);
if($matches !== false)
{
echo "Found the word \"$word\" in the following files: " . implode(', ', $matches) . "\n";
}
else
{
echo "Unable to find the word \"$word\" in the index\n";
}
}</lang>
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