How to showing the date_part all

I have a data array's like this. and I want to make this data into grafik. and the problem is when i put the script

if (isset($b['admin'])) {
      echo $b['admin'];
      $series = $this->HighCharts->addChartSeries();
      $series->addName($user)->addData([(int)$b['admin']]);
      $mychart->addSeries($series);
}

in the foreach($datas as $a){. why the date_part 3 couldn't be show?

QUERY RESULT ARRAY

$array = array(
        (int) 0 => array( 
                        'B' => array(
                                    'company' => 'ABC' 
                        ), 
                        'User' => array( 
                                    'company' => 'abc' 
                        ), 
                        (int) 0 => array(
                                    'date_part' => '3',
                                    'jumlah' => null, 
                                    'jumbuy' => '50990', 
                                    'admin' => '50010' 
                        )
        ),
        (int) 1 => array(
                        'B' => array( 
                                    'company' => 'BCD'
                        ), 
                        'User' => array( 
                                    'company' => 'bcd' 
                        ), 
                        (int) 0 => array( 
                                    'date_part' => '3',
                                    'jumlah' => null, 
                                    'jumbuy' => '65000', 
                                    'admin' => '5000' )
        ),
        (int) 2 => array(
                        'B' => array(
                                    'company' => 'ABC' 
                        ), 
                        'User' => array( 
                                    'company' => 'abc' 
                        ), 
                        (int) 0 => array(
                                    'date_part' => '4',
                                    'jumlah' => null, 
                                    'jumbuy' => '98990', 
                                    'admin' => '2010' )
        ),
        (int) 3 => array(
                        'B' => array(
                                    'company' => 'CDE'
                        ), 'User' => array( 
                                    'company' => 'cde' 
                        ), 
                        (int) 0 => array(
                                    'date_part' => '4',
                                    'jumlah' => null, 
                                    'jumbuy' => '34566', 
                                    'admin' => '2010' )
        ),
        (int) 4 => array(
                        'B' => array( 
                                    'company' => 'BCD'
                        ), 
                        'User' => array( 
                                    'company' => 'bcd' 
                        ), 
                        (int) 0 => array( 
                                    'date_part' => '4',
                                    'jumlah' => null, 
                                    'jumbuy' => '9000', 
                                    'admin' => '5000' )
        ),
);

IN CONTROLLERS

$chartName = 'Line Chart with Data Labels';
$tooltipFormatFunction = <<<EOF
function() { return '<b>'+ this.series.name +'</b><br/>'+ this.x +': '+ this.y +'°C';}
EOF;

    $mychart = $this->HighCharts->create($chartName, 'line');

    $data = array();
    foreach($report_posts as $values) {
        if (!isset($data[$values['User']['company']])) {
            $data[$values['User']['company']] = $values;
        } else {
            $last_element = array_pop($values);
            $data[$values['User']['company']][] = $last_element;
        }
    }
    $datas = array_values($data);

    foreach ($datas as $a) {
            $user = [$a['User']['company']];
            foreach ($a as $b) {
                if (isset($b['date_part'])) {
                    $this->HighCharts->setChartParams($chartName, array(
                            'renderTo' => 'linewrapper', // div to display chart inside
                            'chartWidth' => 1000,
                            'chartHeight' => 750,
                            'chartMarginTop' => 60,
                            'chartMarginLeft' => 90,
                            'chartMarginRight' => 30,
                            'chartMarginBottom' => 110,
                            'chartSpacingRight' => 10,
                            'chartSpacingBottom' => 15,
                            'chartSpacingLeft' => 0,
                            'chartAlignTicks' => FALSE,
                            'chartTheme' => 'dark-green',
                            'title' => 'Monthly Average Temperature',
                            'subtitle' => 'Source: WorldClimate.com',
                            'titleAlign' => 'center',
                            'titleFloating' => TRUE,
                            'titleStyleFont' => '18px Metrophobic, Arial, sans-serif',
                            'titleStyleColor' => '#0099ff',
                            'titleX' => 20,
                            'titleY' => 10,
                            'legendEnabled' => TRUE,
                            'legendLayout' => 'horizontal',
                            'legendAlign' => 'center',
                            'legendVerticalAlign ' => 'bottom',
                            'legendItemStyle' => array('color' => '#222'),
                            'legendBackgroundColorLinearGradient' => array(0, 0, 0, 25),
                            'legendBackgroundColorStops' => array(array(0, 'rgb(217, 217, 217)'), array(1, 'rgb(255, 255, 255)')),
                            'tooltipEnabled' => TRUE,
                            'tooltipFormatter' => $tooltipFormatFunction,
                            'xAxisLabelsEnabled' => TRUE,
                            'xAxisLabelsAlign' => 'right',
                            'xAxisLabelsStep' => 1,
                            'xAxislabelsX' => 5,
                            'xAxisLabelsY' => 20,
                            'xAxisCategories' => [$b['date_part']],
                            'yAxisTitleText' => 'Admin',
                            'plotOptionsLineDataLabelsEnabled' => TRUE,
                            'plotOptionsLineEnableMouseTracking' => TRUE,
                            'enableAutoStep' => FALSE
                        )
                    );
                }//end if

            }//end foreach

        if (isset($b['admin'])) {
            echo $b['admin'];
            $series = $this->HighCharts->addChartSeries();
            $series->addName($user)->addData([(int)$b['admin']]);
            $mychart->addSeries($series);
        }

    }