Retrieve XML attribute value in Scala

Question

Suppose I need to get the attribute value in Scala. I can assume that the attribute is a string (and if it is not this is an error).

Since the scala.xml API (MetaData.get(name: String):Option[Seq[Node]]) looks rather complex I wrote a helper function:

 def attributeValue(e: Elem, aname: String): Option[String] = for {
   seq <- e.attributes.get(aname)
   value <- seq.collectFirst {case Text(txt) => txt}
 } yield value

Does it make sense ? How would you change/fix this code

Norbert Radyk · Accepted Answer · 2014-06-12 09:36:50Z

2

How about using the \ operator to extract attribute value:

  def attributeValue(e: Elem, attributeName: String): Option[String] =
    (e \ s"@$attributeName").collectFirst { case Text(txt) => txt }

Please note, in some cases you might want to simplify it even more (as shown below), however in this case the empty string will be returned if attribute is not found (which is probably not what you're after):

  def attributeValue(e: Elem, attributeName: String): String =
    (e \ s"@$attributeName").text

answered Jun 12, 2014 at 9:36

Norbert Radyk

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2 Comments

Michael Over a year ago

Thanks. Looks similar to e.attributes.get(aname).collectFirst{case Text(txt) => txt}. I thought that the for-comprehension improves readability.

Michael Over a year ago

BTW, I do not get why attributes.get returns Option of Seq[Node] instead of Option of String.

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