PHP 中的多维数组中的排序理解问题

Question

我正在尝试对多维数组进行排序。该数组包含城市和人口。这些显示在 table.I 想要按升序排序的 Population 列中。我明白，程序是sort($array_variable)，但我不知道如何在排序后打印它们。请帮我教育一下这件事。程序如下

<html>
<head>
    <style>
        table, tr, td, th {
            border:1px solid blue;
            border-collapse: collapse;
        }
    </style>
</head>
<body>
    <?php
    $data=array (
        array('New York','Washington',8008278),
        array('Los Angeles','California',3694820),
        array('Chicago','Illinois',2896016),
        array('Houston','Texas',1953631),
        array('Philadelphia','Philadelphia',1517550),
        array('Pheonix','Arizona',1321045),
        array('San Diego','California',1223400),
        array('Dallas','Texas',188580),
        array('San Antonio','Texas',144646),
        array('Detroit','Michigan',951270),                        
    );
    print '<table>';

    print '<th>'; print "City"; print '</th>';
    print '<th>'; print "State"; print '</th>';
    print '<th>'; print "Population"; print '</th>';

    print '<tr>';
    print '<td>'; print $data[0][0]; print '</td>';
    print '<td>'; print $data[0][1]; print '</td>';
    print '<td>'; print $data[0][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print $data[1][0]; print '</td>';
    print '<td>'; print $data[1][1]; print '</td>';
    print '<td>'; print $data[1][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print $data[2][0]; print '</td>';
    print '<td>'; print $data[2][1]; print '</td>';
    print '<td>'; print $data[2][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print $data[3][0]; print '</td>';
    print '<td>'; print $data[3][1]; print '</td>';
    print '<td>'; print $data[3][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print $data[4][0]; print '</td>';
    print '<td>'; print $data[4][1]; print '</td>';
    print '<td>'; print $data[4][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print $data[5][0]; print '</td>';
    print '<td>'; print $data[5][1]; print '</td>';
    print '<td>'; print $data[5][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print $data[6][0]; print '</td>';
    print '<td>'; print $data[6][1]; print '</td>';
    print '<td>'; print $data[6][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print $data[7][0]; print '</td>';
    print '<td>'; print $data[7][1]; print '</td>';
    print '<td>'; print $data[7][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print $data[8][0]; print '</td>';
    print '<td>'; print $data[8][1]; print '</td>';
    print '<td>'; print $data[8][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print $data[9][0]; print '</td>';
    print '<td>'; print $data[9][1]; print '</td>';
    print '<td>'; print $data[9][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td colspan=2>'; print "Total Population is:";  
    print '</td>';
    print '<td>'; print $data[0][2]+$data[1][2]+$data[2][2]+$data[3][2]+$data[4][2]+$data[5][2]+$data[6][2]+$data[7][2]+$data[8][2]+$data[9][2]; print '</td>';
    print '</tr>';

    print '<tr>';
    print '<td>'; print sort($data); print '</td>';
    print '</tr>';        
    print '</table>';
    ?>
</body>

抱歉，节目太长了，这里是菜鸟。如你所见。我已经给出了一个 sort() 函数，但它没有给出所需的输出。谢谢。

Answer 1

尝试：

<table>
  <tr> 
    <th> City </th>
    <th> State </th>
    <th> Population </th>
  </tr>
  <?php 
   $totalPop = 0; 
   foreach($data as $d) { ?>
      <tr> 
         <th> <?php echo $d[0]; ?> </th>
         <th> <?php echo $d[1]; ?> </th>
         <th> <?php echo $d[2]; $totalPop += $d[2]; ?> </th>
      </tr>
  <?php } ?>
  <tr>
    <td colspan="2"> Total Population is: </td>
    <td><?php echo $totalPop; ?></td>
  </tr>

</table>

Answer 2

请尝试

<?php
$data = array(
    array('New York', 'Washington', 8008278),
    array('Los Angeles', 'California', 3694820),
    array('Chicago', 'Illinois', 2896016),
    array('Houston', 'Texas', 1953631),
    array('Philadelphia', 'Philadelphia', 1517550),
    array('Pheonix', 'Arizona', 1321045),
    array('San Diego', 'California', 1223400),
    array('Dallas', 'Texas', 188580),
    array('San Antonio', 'Texas', 144646),
    array('Detroit', 'Michigan', 951270),
);

usort($data, function($a, $b) {
    return $a[2] - $b[2];
});
?>
<table>
    <tr>
    <th>City</th>
    <th>State</th>
    <th>Population</th>
    </tr>
    <?php
    $totalPopulation=0;
foreach($data as $d)
{
    ?>
    <tr>
    <td><?php echo $d[0];?></td>
    <td><?php echo $d[1];?></td>
    <td><?php echo $d[2];?></td>
    </tr>
    <?php
    $totalPopulation = $totalPopulation+$d[2];
}
?>
    <tr><td>Total Population</td><td colspan="2"><?php echo $totalPopulation; ?></td></tr>
</table>

Answer 3

只需使用循环打印出数据即可。另外我会创建一个 class City 并使用 usort 来基于 population 属性进行比较。像这样：

<?php

class City{
    public $population;
    public $name;
    public $state;

    public function __construct($name,$state,$population) {
    $this->name = $name;
    $this->state = $state;
    $this->population = $population;
    }

}
$data=array (          
        new City('New York','Washington',8008278),
        new City('Los Angeles','California',3694820),
        new City('Chicago','Illinois',2896016),
        new City('Houston','Texas',1953631),
        new City('Philadelphia','Philadelphia',1517550),
        new City('Pheonix','Arizona',1321045),
        new City('San Diego','California',1223400),
        new City('Dallas','Texas',188580),
        new City('San Antonio','Texas',144646),
        new City('Detroit','Michigan',951270)              
    );


usort($data, function($a, $b)
{
    return $a->population < $b->population;
});

print '<table>';
    print '<tr>';
    print '<th>'; print "City"; print '</th>';
    print '<th>'; print "State"; print '</th>';
    print '<th>'; print "Population"; print '</th>';
    print '</tr>';


foreach($data as $currCity){    
    print '<tr>';
    print '<td>'; print $currCity->name; print '</td>';
    print '<td>'; print $currCity->state; print '</td>';
    print '<td>'; print $currCity->population; print '</td>';
    print '</tr>';

}

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