Piwik\Plugins\CoreVisualizations\JqplotDataGenerator::getUnitsForColumnsToDisplay PHP Method

    protected function getUnitsForColumnsToDisplay()
    {
        // derive units from column names
        $units = $this->deriveUnitsFromRequestedColumnNames();
        if (!empty($this->properties['y_axis_unit'])) {
            $units = array_fill(0, count($units), $this->properties['y_axis_unit']);
        }
        // the bar charts contain the labels a first series
        // this series has to be removed from the units
        reset($units);
        if ($this->graphType == 'bar' && key($units) == 'label') {
            array_shift($units);
        }
        return $units;
    }