Piwik\Plugins\CoreHome\DataTableRowAction\RowEvolution::getFirstAndLastDataPointsForMetric PHP Method

    private function getFirstAndLastDataPointsForMetric($metric)
    {
        $first = 0;
        $firstTable = $this->dataTable->getFirstRow();
        if (!empty($firstTable)) {
            $row = $firstTable->getFirstRow();
            if (!empty($row)) {
                $first = floatval($row->getColumn($metric));
            }
        }
        $last = 0;
        $lastTable = $this->dataTable->getLastRow();
        if (!empty($lastTable)) {
            $row = $lastTable->getFirstRow();
            if (!empty($row)) {
                $last = floatval($row->getColumn($metric));
            }
        }
        return array($first, $last);
    }