动态访问嵌套对象 [英] Dynamically access nested object
问题描述
我正在构建一个可以利用多种Web服务进行地理编码的Geocoding类（即Google，Yahoo，Bing等）。我试图用这种方式来实现新的web服务可以很容易地配置。大多数Web服务返回XML / JSON ..对于PHP，我选择XML作为我的主要焦点。所有的代码已经存在，但现在谷歌返回下面的XML（转换为simple_xml_element）
SimpleXMLElement Object
（
[status] => OK
[result] => Array
（
[0] => SimpleXMLElement Object
（
[type] => postal_code
[formatted_address] => 1010瑞士洛桑
[address_component] => Array
（
[0] => SimpleXMLElement对象
（
[long_name] => 1010
[短名称] => 1010
[类型] =>邮政编码
）
[1] => SimpleXMLElement对象
（
[long_name] =>洛桑
[short_name] =>洛桑
[type] => Array
（
[0] => locality
[1] =>政治
）
）
[2] => SimpleXMLElement Object
（
[long_name] => Vaud
[short_name] => VD
[type] => Array
（
[ 0] => administrative_area_level_1
[1] =>政治
）
）
[3] => SimpleXMLElement Object
（
[long_name] => Switzerland
[short_name] => CH
[type] => Array
（
[ 0] => country
[1] =>政治
）
）
）
[geometry ] => SimpleXMLElement对象
（
[位置] => SimpleXMLElement对象
（
[lat] => 46.5376186
[lng] => 6.6539665
）
[location_type] => APPROXIMATE
[viewport] => SimpleXMLElement Object
（
[southwest] => SimpleXMLElement Object
[lat] => 46.5253574
[lng] => 6.6384420
）
[northeast] => SimpleXMLElement对象
（
[lat] => 46.5467887
[lng] => 6.6745222
）
）
[bounds] => SimpleXMLElement对象
（
[southwest] => SimpleXMLElement对象
（
[lat] => 46.5253574
[lng] => 6.6384420
）
[northeast] => SimpleXMLElement对象
（
[lat] => 46.5467887
[lng] => 6.6745222
）$ b b b b b b b b b b b b b b b b b b b b b b c $ c
我需要的信息位于[location]标记中，因此我试图将路径存储在var中：
$ lat_path ='result [0] - >> geometry-> location-> lat;
然后尝试以这种方式访问该值：
（假设$ xml是对象）
$ xml-> {$ lat_path};
但这并不奏效。有没有什么办法可以基于动态或变量来访问信息。我不想用Google特定的代码破坏我的Geocoding方法。
谢谢！
解决方案当你做的时候
$ xml-> {$ lat_path};
PHP将使用 $ lat_path 中的任何内容作为变量名称。它不会进入对象图或完全服从 T_OBJECT_OPERATOR 。它只会寻找一个属性
'result [0] - > geometry-> location-> lat;'
位于 $ xml 中。尝试运行以下代码作为示例：
$ obj = new StdClass;
$ obj-> {'result [0] - > geometry-> location-> lat;'} = 1;
print_r（$ obj）;
它会输出
stdClass Object
（
[result [0] - > geometry-> location-> lat;] => 1
）
正如您所看到的，它是一个单独的属性，而不是嵌套的对象图。
像评论中提示的一样，可以使用XPath或直接转到期望值：
$ xml- >导致[0] - >几何性质 - >位置 - > LAT;
I'm building a Geocoding class that can utilize multiple webservices for Geocoding (ie Google, Yahoo, Bing, etc.). I'm trying to make it in a such a way that new webservices can be easily configured. Most of the webservices return either XML/JSON.. for PHP I chose XML as my primary focus. All the code is already in place, but now Google for instance returns the following XML (transformed to a simple_xml_element)
SimpleXMLElement Object
(
[status] => OK
[result] => Array
(
[0] => SimpleXMLElement Object
(
[type] => postal_code
[formatted_address] => 1010 Lausanne, Switzerland
[address_component] => Array
(
[0] => SimpleXMLElement Object
(
[long_name] => 1010
[short_name] => 1010
[type] => postal_code
)
[1] => SimpleXMLElement Object
(
[long_name] => Lausanne
[short_name] => Lausanne
[type] => Array
(
[0] => locality
[1] => political
)
)
[2] => SimpleXMLElement Object
(
[long_name] => Vaud
[short_name] => VD
[type] => Array
(
[0] => administrative_area_level_1
[1] => political
)
)
[3] => SimpleXMLElement Object
(
[long_name] => Switzerland
[short_name] => CH
[type] => Array
(
[0] => country
[1] => political
)
)
)
[geometry] => SimpleXMLElement Object
(
[location] => SimpleXMLElement Object
(
[lat] => 46.5376186
[lng] => 6.6539665
)
[location_type] => APPROXIMATE
[viewport] => SimpleXMLElement Object
(
[southwest] => SimpleXMLElement Object
(
[lat] => 46.5253574
[lng] => 6.6384420
)
[northeast] => SimpleXMLElement Object
(
[lat] => 46.5467887
[lng] => 6.6745222
)
)
[bounds] => SimpleXMLElement Object
(
[southwest] => SimpleXMLElement Object
(
[lat] => 46.5253574
[lng] => 6.6384420
)
[northeast] => SimpleXMLElement Object
(
[lat] => 46.5467887
[lng] => 6.6745222
)
)
)
)
)
The information I need is in the [location] tag, so I've tried storing the path in a var:
$lat_path = 'result[0]->geometry->location->lat;
And then try to access the value this way:
(suppose $xml is the object)
$xml->{$lat_path};
But this doens't work. Is there any way I can access the information dynamically or variable based. I do not want to ruin my Geocoding method with Google specific code.
Thanks!
解决方案 When you do
$xml->{$lat_path};
PHP will use anything within $lat_path as the variable name. It will not go into the object graph or obey the T_OBJECT_OPERATOR at all. It will simply look for a property
'result[0]->geometry->location->lat;'
in $xml. Try to run this code for an example:
$obj = new StdClass;
$obj->{'result[0]->geometry->location->lat;'} = 1;
print_r($obj);
It will output
stdClass Object
(
[result[0]->geometry->location->lat;] => 1
)
As you can see, it is one single property, not a nested object graph.
Like suggested in the comments, either use XPath or go to the desired value directly:
$xml->result[0]->geometry->location->lat;
这篇关于动态访问嵌套对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
