Extract

WARNING

Extract operations are not yet well optimized about memory consumption. Some of them have the potential to do significantly more in the future, but others won't really be able to.

The Extract object offers an API to return a NEW DataFrame without modifying anything from the original DataFrame. It's also possible to export a Select object to a new DataFrame, but Extract API also offer transformations methods.

// To a new Data Frame
$df->extract()->....

// To a custom dataFrame (useful for alternatives data-drivers)
$newDf = new DataFrame(dataDriver: $pdoSqlDriver);
$df->extract(to: $newDf)->...

Clone

$newDf = $df->extract()->clone();
$newDf = clone $df; // equivalent

Extract DataFrame from SQL

$df = DataFrame::fromArray([
    ['a' => 1, 'b' => 2, 'c' => 3],
    ['a' => 4, 'b' => 5, 'c' => 6],
    ['a' => 7, 'b' => 8, 'c' => 9],
]);

$resultingDf = $df->extract()->fromSqlQuery(" SELECT
                        a,
                        b
                        FROM dataframe
                        WHERE a = '4'
                        OR b = '2';
                    ");

// $resultingDf To Be:
[
    0 => ['a' => 1, 'b' => 2],
    1 => ['a' => 4, 'b' => 5]
]

withFilter

$df = DataFrame::fromArray([
    ['a' => 1, 'b' => 2, 'c' => 3],
    ['a' => 4, 'b' => 5, 'c' => 6],
    ['a' => 7, 'b' => 8, 'c' => 9],
]);

$newDf = $df->extract()->withFilter(static function (array $record, int $key) {
    return $record['a'] > 4 || $record['a'] < 4;
});

$newDf->toArray();
// To Be:
[
    ['a' => 1, 'b' => 2, 'c' => 3],
    ['a' => 7, 'b' => 8, 'c' => 9],
];

Unique

$df = DataFrame::fromArray([
    ['a' => 1, 'b' => 2, 'c' => 3],
    ['a' => 1, 'b' => 3, 'c' => 4],
    ['a' => 2, 'b' => 4, 'c' => 5],
    ['a' => 2, 'b' => 4, 'c' => 6],
    ['a' => 3, 'b' => 5, 'c' => 7],
    ['a' => 3, 'b' => 5, 'c' => 8],
]);

$newDf = $df->extract()->unique('a');
$newDf->toArray():
// To Be:
[
    ['a' => 1],
    ['a' => 2],
    ['a' => 3],
];

$newDf = $df->extract()->unique(['a', 'b']);
$newDf->toArray():
// To Be:
[
    ['a' => 1, 'b' => 2],
    ['a' => 1, 'b' => 3],
    ['a' => 2, 'b' => 4],
    ['a' => 3, 'b' => 5],
];