如何计算codeigniter中的中位数

Question

我需要创建具有总数，平均值和中位数的表。现在我创建了总数和平均数。我的问题是如何找到中位数？我会动态地检索我的值到表。 这是我的编码，每个数据都在变量$ result和$ result1。

      <table class="footable">
             <thead>
                 <tr>
                 <th  data-class="expand" data-sort-initial="true"  style="text-align:center;" >State</th>
                 <th  style="text-align:center;" >Final FY2010-11 Budget</th>
                 <th data-class="expand" data-type="numeric" style="text-align:center;" >Provisional FY2011-12 Budget</th>
                 <th data-class="expand" data-type="numeric" style="text-align:center;" >% Change</th>
                 </tr>
            </thead>
        <tbody>
        <?php
        for($i=0;$i<count($result);$i++) {
        $this->actual_total += $result[$i]->breakdown_grants;
        $this->provisional_total += $result1[$i]->breakdown_grants;
        $this->actual_avg = $this->actual_total/count($result);
        $this->provisional_avg = $this->provisional_total/count($result1);
        $this->change = ($result[$i]->breakdown_grants + $result1[$i]->breakdown_grants)/100;
        $this->total_change = ($this->actual_total + $this->provisional_total )/100;
        $this->avg_change = ($this->actual_avg + $this->provisional_avg )/100;



         ?>
            <tr>

            <td style="text-align:center;" >
                <span><?php echo $result[$i]->state; ?></span>
            </td>
            <td  style="text-align:center;"  >
                <span><?php echo $result[$i]->breakdown_grants; ?></span>
            </td>

            <td  style="text-align:center;" >
                <span><?php echo $result1[$i]->breakdown_grants; ?></span>
            </td>

            <td  style="text-align:center;" >
                <span><?php echo $this->change." %" ; ?></span>
            </td>

            </tr>
        <?php }  ?>
        </tbody>
    </table>

     <br/>

     <table class="new">
        <thead>
                 <tr>
                 <th></th>
                <th style="text-align:center;">Final FY2010-11 Budget</th>
                 <th style="text-align:center;">Provisional FY2011-12 Budget</th>
                 <th style="text-align:center;">% Change</th>
                 </tr>
        </thead>
        <tbody>
            <tr>

            <td style="text-align:center;" >
                <span>TOTAL</span>
            </td>
            <td style="text-align:center;">
                <span><?php echo $this->actual_total; ?></span>
            </td>

            <td style="text-align:center;">
                <span><?php echo $this->provisional_total; ?></span>
            </td>
            <td style="text-align:center;">
                <span><?php echo $this->total_change." %" ; ?></span>
            </td>
            </tr>
            <tr>

            <td style="text-align:center;">
                <span>AVERAGE</span>
            </td>
            <td style="text-align:center;">
                <span><?php echo $this->actual_avg; ?></span>
            </td>

            <td style="text-align:center;">
                <span><?php echo $this->provisional_avg; ?></span>
            </td>
            <td style="text-align:center;">
                <span><?php echo $this->avg_change." %" ; ?></span>
            </td>

            </tr>
            <tr>

            <td style="text-align:center;">
                <span>MEDIAN</span>
            </td>
            <td style="text-align:center;">
                <span><?php echo $this->actual_avg; ?></span>
            </td>

            <td style="text-align:center;">
                <span><?php echo $this->provisional_avg; ?></span>
            </td>
            <td style="text-align:center;">
                <span><?php echo $this->avg_change." %" ; ?></span>
            </td>

            </tr>

        </tbody>
    </table>

这是我的模型编码

function reports_details1() {
        $this->db->select('budget_breakdown.breakdown_grants');//survey_respondent_info.state,survey_respondent_info.survey_id,budgets.budget_id,
        $this->db->from('survey_respondent_info');
        $this->db->join('budgets', 'budgets.survey_id=survey_respondent_info.survey_id' , 'left');
        $this->db->join('budget_breakdown', 'budgets.budget_id=budget_breakdown.budget_id' , 'left');
        $this->db->where('budgets.budget_option_id', 2);
        $query1 = $this->db->get();
        $result = $query1->result();
        return $result;
    }