我试图计算节点出现在我的xml中的次数并将此数字存储在变量中:
<?PHP $xmlStr = file_get_contents('books.xml'); $xml = new SimpleXMLElement($xmlStr); $res = $xml->xpath("count(catalog/book)"); print_r($res); ?>
XML:
<?xml version="1.0"?> <catalog> <book id="bk101"> <author>Gambardella,Matthew</author> <title>XML Developer's Guide</title> <genre>Computer</genre> <price>44.95</price> <publish_date>2000-10-01</publish_date> <description>An in-depth look at creating applications with XML.</description> </book> <book id="bk102"> <author>Ralls,Kim</author> <title>Midnight Rain</title> <genre>Fantasy</genre> <price>5.95</price> <publish_date>2000-12-16</publish_date> <description>A former architect battles corporate zombies,an evil sorceress,and her own childhood to become queen of the world.</description> </book> <book id="bk103"> <author>Corets,Eva</author> <title>Maeve Ascendant</title> <genre>Fantasy</genre> <price>5.95</price> <publish_date>2000-11-17</publish_date> <description>After the collapse of a nanotechnology society in England,the young survivors lay the foundation for a new society.</description> </book> <book id="bk104"> <author>Corets,Eva</author> <title>Oberon's Legacy</title> <genre>Fantasy</genre> <price>5.95</price> <publish_date>2001-03-10</publish_date> <description>In post-apocalypse England,the mysterIoUs agent kNown only as Oberon helps to create a new life for the inhabitants of London. Sequel to Maeve Ascendant.</description> </book> <book id="bk105"> <author>Corets,Eva</author> <title>The Sundered Grail</title> <genre>Fantasy</genre> <price>5.95</price> <publish_date>2001-09-10</publish_date> <description>The two daughters of Maeve,half-sisters,battle one another for control of England. Sequel to Oberon's Legacy.</description> </book> <book id="bk106"> <author>Randall,Cynthia</author> <title>lover Birds</title> <genre>Romance</genre> <price>4.95</price> <publish_date>2000-09-02</publish_date> <description>When Carla meets Paul at an ornithology conference,tempers fly as feathers get ruffled.</description> </book> <book id="bk107"> <author>Thurman,Paula</author> <title>Splish Splash</title> <genre>Romance</genre> <price>4.95</price> <publish_date>2000-11-02</publish_date> <description>A deep sea diver finds true love twenty thousand leagues beneath the sea.</description> </book> <book id="bk108"> <author>Knorr,Stefan</author> <title>Creepy Crawlies</title> <genre>Horror</genre> <price>4.95</price> <publish_date>2000-12-06</publish_date> <description>An anthology of horror stories about roaches,centipedes,scorpions and other insects.</description> </book> <book id="bk109"> <author>Kress,Peter</author> <title>Paradox Lost</title> <genre>Science Fiction</genre> <price>6.95</price> <publish_date>2000-11-02</publish_date> <description>After an inadvertant trip through a Heisenberg Uncertainty Device,James Salway discovers the problems of being quantum.</description> </book> <book id="bk110"> <author>O'Brien,Tim</author> <title>Microsoft .NET: The Programming Bible</title> <genre>Computer</genre> <price>36.95</price> <publish_date>2000-12-09</publish_date> <description>Microsoft's .NET initiative is explored in detail in this deep programmer's reference.</description> </book> <book id="bk111"> <author>O'Brien,Tim</author> <title>MSXML3: A Comprehensive Guide</title> <genre>Computer</genre> <price>36.95</price> <publish_date>2000-12-01</publish_date> <description>The Microsoft MSXML3 parser is covered in detail,with attention to XML DOM interfaces,XSLT processing,SAX and more.</description> </book> <book id="bk112"> <author>galos,Mike</author> <title>Visual Studio 7: A Comprehensive Guide</title> <genre>Computer</genre> <price>49.95</price> <publish_date>2001-04-16</publish_date> <description>Microsoft Visual Studio 7 is explored in depth,looking at how Visual Basic,Visual C++,C#,and ASP+ are integrated into a comprehensive development environment.</description> </book> </catalog>
以下将在屏幕上打印出一系列书籍:
<?PHP $xmlStr = file_get_contents('books.xml'); $xml = new SimpleXMLElement($xmlStr); $res = $xml->xpath("/catalog/book"); print_r($res); ?>
我只是无法弄清楚为什么count函数不起作用.
解决方法
您可以直接在$res上使用count(),而不是在xpath中应用它.
echo count($res);
原因是xpath返回SimpleXMLElement类型的数组,该数组包含xpath参数路径中的所有节点.
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