排序对象（SimpleXMLElement）php

Question

我正在尝试找到一种方法来对 SimpleXMLElement 中的数组进行排序。我想按可以从 event_start_dt 获得的开始时间进行排序。我还想按房间 ID 排序作为一个单独的过程。目前该数组按 object(SimpleXMLElement) # 排序。这是 var_dump($array):

    object(SimpleXMLElement)#275 (1) { 
["reservation"]=> array(3) 
    { 
    [0]=> object(SimpleXMLElement)#287 (28) { 
        ["reservation_id"]=> string(7) "8644894" 
        ["event_start_dt"]=> string(25) "2013-12-02T12:00:00-08:00" 
        ["event_end_dt"]=> string(25) "2013-12-02T13:00:00-08:00" 
        ["event_id"]=> string(6) "314147" 
        ["event_name"]=> string(24) "Practice" 
        ["room_id"]=> string(3) "202"
    }
    [1]=> object(SimpleXMLElement)#288 (28) { 
        ["reservation_id"]=> string(7) "8595185" 
        ["event_start_dt"]=> string(25) "2013-12-02T08:00:00-08:00" 
        ["event_end_dt"]=> string(25) "2013-12-02T09:00:00-08:00" 
        ["event_id"]=> string(6) "314005"
        ["event_name"]=> string(24) "Meeting" 
        ["room_id"]=> string(3) "207"
    }
    [2]=> object(SimpleXMLElement)#289 (28) { 
        ["reservation_id"]=> string(7) "8718654" 
        ["event_start_dt"]=> string(25) "2013-12-02T10:00:00-08:00" 
        ["event_end_dt"]=> string(25) "2013-12-02T11:00:00-08:00" 
        ["event_id"]=> string(6) "315811" 
        ["event_name"]=> string(20) "Maintenance" 
        ["room_id"]=> string(3) "202"
    }
} }

我已经尝试过 usort 和 asort 但都没有让它与任何一种方法一起使用。

usort 方法：

function sortByTime($a, $b){
    $a = strtotime($array->event_start_dt);
    $b = strtotime($array->event_start_dt);
        if ($a==$b) return 0;
        return ($a < $b) ?-1 : 1;
        }

        usort($arrTimes, 'sortByTime');

        var_dump($arrTimes);

尝试下面的代码会给我一个警告：usort() 期望参数 1 是数组，给定对象。

foreach ($rez->reservation as $value){ 
    $var1 = $value->space_reservation->space_name;
    $var2 = substr($value->event_start_dt,11,5);
}
sort_obj_arr($value,$var1,SORT_DESC);

echo "<pre>SORTED ";
print_r($value);
echo "</pre>";

function sort_obj_arr(& $arr, $sort_field, $sort_direction)
{
    $sort_func = function($obj_1, $obj_2) use ($sort_field, &$sort_direction)
    {
        if ($sort_direction == SORT_ASC) {
            return strnatcasecmp($obj_1->$sort_field, $obj_2->$sort_field);
        } else {
            return strnatcasecmp($obj_2->$sort_field, $obj_1->$sort_field);
        }
    };
    usort($arr, $sort_func);

}

我的控制器有一个数组，但无法让 usort 工作： 我得到： usort() 期望参数 1 是数组、给定对象或 null。

$array = array($this->data);
print_r($array);

array(1) { 
[0]=> object(SimpleXMLElement)#280 (1) { ["reservation"]=> array(3) { 
        [0]=> object(SimpleXMLElement)#287 (28) { 
            ["reservation_id"]=> string(7) "8644894" 
            ["event_start_dt"]=> string(25) "2013-12-02T12:00:00-08:00" 
            ["event_end_dt"]=> string(25) "2013-12-02T13:00:00-08:00" 
            ["event_id"]=> string(6) "314147" 
            ["event_name"]=> string(24) "Practice" 
            ["room_id"]=> string(3) "202"
        }
        [1]=> object(SimpleXMLElement)#288 (28) { 
            ["reservation_id"]=> string(7) "8595185" 
            ["event_start_dt"]=> string(25) "2013-12-02T08:00:00-08:00" 
            ["event_end_dt"]=> string(25) "2013-12-02T09:00:00-08:00" 
            ["event_id"]=> string(6) "314005"
            ["event_name"]=> string(24) "Meeting" 
            ["room_id"]=> string(3) "207"
        }
        [2]=> object(SimpleXMLElement)#289 (28) { 
            ["reservation_id"]=> string(7) "8718654" 
            ["event_start_dt"]=> string(25) "2013-12-02T10:00:00-08:00" 
            ["event_end_dt"]=> string(25) "2013-12-02T11:00:00-08:00" 
            ["event_id"]=> string(6) "315811" 
            ["event_name"]=> string(20) "Maintenance" 
            ["room_id"]=> string(3) "202"
        }
    } }

请求 print_r：

SimpleXMLElement Object
(
    [reservation] => Array(3)
        (
            [0] => SimpleXMLElement Object
                (
                    [reservation_id] => 8604174
                    [event_start_dt] => 2013-12-31T06:00:00-08:00
                    [event_end_dt] => 2013-12-31T08:00:00-08:00
                    [event_id] => 314147
                    [event_name] => Practice
                    [room_id] => 202
                 )
         [1] => SimpleXMLElement Object
                (
                    [reservation_id] => 8604177
                    [event_start_dt] => 2013-12-31T05:00:00-08:00
                    [event_end_dt] => 2013-12-31T06:00:00-08:00
                    [event_id] => 314150
                    [event_name] => Meeting
                    [room_id] => 216
                 )
         [2] => SimpleXMLElement Object
                (
                    [reservation_id] => 8604189
                    [event_start_dt] => 2013-12-31T10:00:00-08:00
                    [event_end_dt] => 2013-12-31T11:00:00-08:00
                    [event_id] => 314150
                    [event_name] => Maintenance
                    [room_id] => 220
                 )
)
)

$arrTimes = xml2array($array->reservation);

var_dump($arrTimes)

array(5) { 
["reservation_id"]=> string(7) "8604175" 
["event_start_dt"]=> string(25) "2014-01-02T06:00:00-08:00" 
["event_end_dt"]=> string(25) "2014-01-02T08:00:00-08:00" 
["event_id"]=> string(6) "314147" 
["event_name"]=> string(24) "Practice" 
}

Answer 1

您必须使用 json encode decode 将 frist in 转换为 xml 到数组

$xml_array = json_decode(json_encode((array)$xml), TRUE);

你会得到数组列表......然后你可以使用 strtotime 函数根据日期进行排序。

Answer 2

使用array_multisort

            foreach ($rez->reservation as $value)
            { 
                     $dateTime[] = $value->event_start_dt;
            }

           array_multisort($dateTime,SORT_ASC,SORT_STRING,$rez->reservation);   
           echo "<pre>";
           print_r($rez->reservation);

检查一下。这是我的代码

<?php
        $myarray=array(
                    0 => array
                        (
                            'dateTime' => '2013-12-02T10:00:00-08:00',
                            'chanl1' => '20.10',
                            'chanl2' => '45.4',
                            'chanl3' => '',
                        ),

                    1 => array
                        (
                            'dateTime' => '2013-12-02T11:00:00-08:00',
                            'chanl1' => '20.11',
                            'chanl2' => '45.4',
                            'chanl3' => '',
                        ),
                  2 => array
                        (
                            'dateTime' => '2013-12-02T12:00:00-08:00',
                            'chanl1' => '20.12',
                            'chanl2' => '33.8',
                            'chanl3' => '',
                        ),

                    3 => array
                        (
                            'dateTime' => '2013-12-02T09:00:00-08:00',
                            'chanl1' => '20.9',
                            'chanl2' => '33.9',
                            'chanl3' => ''
                        ));

            foreach($myarray as $c=>$key) {
                    $dateTime[] = $key['dateTime'];                      
            }           


        array_multisort($dateTime,SORT_ASC,SORT_STRING,$myarray);   
        echo "<pre>";
        print_r($myarray);
        ?>

输出是：

Array
(
    [0] => Array
        (
            [dateTime] => 2013-12-02T09:00:00-08:00
            [chanl1] => 20.9
            [chanl2] => 33.9
            [chanl3] => 
        )

    [1] => Array
        (
            [dateTime] => 2013-12-02T10:00:00-08:00
            [chanl1] => 20.10
            [chanl2] => 45.4
            [chanl3] => 
        )

    [2] => Array
        (
            [dateTime] => 2013-12-02T11:00:00-08:00
            [chanl1] => 20.11
            [chanl2] => 45.4
            [chanl3] => 
        )

    [3] => Array
        (
            [dateTime] => 2013-12-02T12:00:00-08:00
            [chanl1] => 20.12
            [chanl2] => 33.8
            [chanl3] => 
        )

)

FIDDLE

Answer 3

在对数据进行排序之前，您需要创建一个数组，其中包含要排序的单独项目作为其值。从您的调试输出来看，这些是输入 XML 中的多个 <reservation> 节点，它们是这些示例中由 $array/$this->data 表示的元素的子节点（它是否是文档的根并不重要） , SimpleXML 没有 Document 对象）。

您的print_r 和var_dump 输出显示您当前没有这样的数组，只有一个SimpleXML 对象：

• 您的第一个示例显示 var_dump($array) 给出以 object(SimpleXMLElement)#275 (1) { 开头的输出 - 忽略后面的单词 array，这就是 var_dump 渲染对象的内部的方式。
• 稍后，您有一个以array(1) { 开头的print_r($array); - 但这只是因为您已将真实数据包装在上面一行 ($array = array($this->data);) 的单元素数组中，并且该元素 (@987654333 @) 显示为object(SimpleXMLElement)#280 (1) { ...。

请注意，无需进一步将所有内部 SimpleXML 对象转换为数组 - 您只需要一个可排序的列表，其中包含您感兴趣的项目。我个人会使用简单而明确的 foreach 循环, 为了最大限度地提高代码可读性，尽管有“更聪明”的解决方案可供使用。

一旦你有了一个可排序的列表，你就需要一个用于usort 的回调函数来比较它的两个参数。您所做的尝试是正确的，但指的是不存在的（在该函数中）变量$array；你需要比较的值是函数的参数，你称之为$a和$b——具体来说，你想比较strtotime($a->event_start_dt)和strtotime($b->event_start_dt)。

您还可以使函数更简单，因为它遵循回调的返回值应该是-1、0 或1 的常见误解。事实上，它可以是任何整数，只有符号很重要——返回 -42 与返回 -999 的效果相同，即在结果数组中将项目 $a 放在 $b 之前。

我不能轻易给出一个经过测试的例子，因为你没有提供底层的 XML 来重现你的输入（例如echo $this->data->asXML();），但我会采取的基本方法是这样的：

// Start with an empty array, and add all the items we're interested in to it
$sortable_array = array();
// Loop over all <reservation> children of the SimpleXML object $this->data
// See http://php.net/manual/en/simplexml.examples-basic.php
foreach ( $this->data->reservation as $reservation_node )
{
    // Add the individual node to our array
    $sortable_array[] = $reservation_node;
}

// Now let's sort out the callback function for the sorting
// This could also be an anonymous function passed directly to usort
function sort_callback_event_start($a, $b)
{
    // $a and $b are both items in our $sortable_array, and therefore
    // <reservation> nodes which we expect to each have a child
    // called <event_start_dt>

    // If we convert both dates to Unix timestamps, we have two integers 
    // to compare, and a simple subtraction gives the desired result
    // of <0, 0, or >0 as documented at http://php.net/usort

    return
        strtotime((string)$a->event_start_dt)
        -
        strtotime((string)$b->event_start_dt);
}

// Now, we have everything we need to do the actual sorting
usort($sortable_array, 'sort_callback_event_start');
// $sortable_array is now sorted as desired! :D

// Note that the items within it are still SimpleXML objects, 
// so you still need to access their properties to do something useful
// e.g. some HTML output with the names listed in order of their start date:
echo '<ol>';
foreach ( $sortable_array as $reservation_node )
{
    echo '<li>', (string)$reservation_node->event_name, '</li>';
}
echo '</ol>';

Answer 4

我将使用此函数（来自 php.net 的示例函数）将其转换为数组。但请注意，这不会对 XML 进行排序，而是对新数组进行排序

/**
* function xml2array
*
* This function is part of the PHP manual.
*
* The PHP manual text and comments are covered by the Creative Commons 
* Attribution 3.0 License, copyright (c) the PHP Documentation Group
*
* @author  k dot antczak at livedata dot pl
* @date    2011-04-22 06:08 UTC
* @link    http://www.php.net/manual/en/ref.simplexml.php#103617
* @license http://www.php.net/license/index.php#doc-lic
* @license http://creativecommons.org/licenses/by/3.0/
* @license CC-BY-3.0 <http://spdx.org/licenses/CC-BY-3.0>
*/
function xml2array ( $xmlObject, $out = array () )
{
  foreach ( (array) $xmlObject as $index => $node )
    $out[$index] = ( is_object ( $node ) ) ? xml2array ( $node ) : $node;

   return $out;
 }

并将 XMLObject 传递给它

$arrTimes = xml2array(YourSimpleXMLElement);

然后在新数组上使用你原来的 usort 函数

 function sortByTime($a, $b){
    $a = strtotime($a['event_start_dt']);
    $b = strtotime($b['event_start_dt']);
    if ($a==$b) 
       return 0;
    return ($a < $b) ? -1 : 1;
 }

终于

usort($arrTimes, 'sortByTime');