关于查找具有与特定值匹配的属性的所有节点

问题描述

我之前在这里看到过以下示例，其中的目标是返回所有节点，这些节点包含一个 id 为 X 且包含值 Y 的属性:

//查找属性为class"且值为test"的所有节点val xml = XML.loadString("""
<span class="test">你好</span><div class="test"><p>hello</p></div></div>""" )def attributeEquals(name: String, value: String)(node: Node) ={node.attribute(name).filter(_==value).isDefined}val testResults = (xml \\ "_").filter(attributeEquals("class","test"))//打印:ArrayBuffer(//<span class="test">你好</span>,//<div class="test"><p>hello</p></div>//)println("测试结果:" + 测试结果)

我使用的是 Scala 2.7，每次返回的打印值始终为空.任何人都可以帮忙吗?抱歉，如果我正在复制另一个线程...但我认为如果我发布一个新线程会更明显吗?

解决方案

根据 Node ScalaDoc，attribute定义如下:

 def 属性(key: String):Option[Seq[Node]]

因此，您应该这样修改您的代码:

def attributeEquals(name: String, value: String)(node: Node) ={node.attribute(name).filter(_.text==value).isDefined//*text* 返回节点的文本表示}

但为什么不实现同样的简单:

scala>(xml 后代或自我)过滤器{节点 =>(node \ "@class").text == "test"}res1: List[scala.xml.Node] = List(<span class="test">hello</span>, <div class="test"><p>hello</p></div>)

I saw the following example disccussed here previously, where the goal was to return all nodes that contain an attribute with an id of X that contains a value Y:

    //find all nodes with an attribute "class" that contains the value "test"
val xml = XML.loadString( """<div>
<span class="test">hello</span>
<div class="test"><p>hello</p></div>
</div>""" )

def attributeEquals(name: String, value: String)(node: Node) =
{
    node.attribute(name).filter(_==value).isDefined
}

val testResults = (xml \\ "_").filter(attributeEquals("class","test"))
//prints: ArrayBuffer(
//<span class="test">hello</span>,
//<div class="test"><p>hello</p></div>
//)
println("testResults: " + testResults)

I am using Scala 2.7 and everytime the return printed value is always empty. Anyone could help on that ?Sorry if I am copying another thread... but thought it would be more visible if I posted a new one ?

解决方案

According to Node ScalaDoc, attribute is defined as follows:

 def attribute(key: String):Option[Seq[Node]]

Therefore, you should modify your code that way:

def attributeEquals(name: String, value: String)(node: Node) =
{
    node.attribute(name).filter(_.text==value).isDefined // *text* returns a text representation of the node
}

But why not just achieving the same simpler:

scala> (xml descendant_or_self) filter{node => (node \ "@class").text == "test"}
res1: List[scala.xml.Node] = List(<span class="test">hello</span>, <div class="test"><p>hello</p></div>)

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