XPath node predicates Martin Holmes Introduction to XSLT for Digital Humanities, Brown University, 08-10 March 2012 Women Writers Project (via website)
url:mailto:wwp@northeastern.edu

Copyright 2011 Martin D. Holmes and the Women Writers Project

This TEI-encoded XML file is available under the terms of the Creative Commons Attribution-ShareAlike 3.0 (Unported) license.

Born digital

 Split instances where an example was immediately followed by its explanation so that the explanation can be elicited before being confirmed. Also fixed link to places file, and wrong answer to one of the questions. added '#' to who values to match what was done in ham.xml; changed an '=' to 'eq' for parallelism Spruced up phrase-level encoding Replaced old change element from another file with this one.
XPath Predicates You use paths and axes in XPath to arrive at specific nodes in your XML. You use predicates to further filter or test those nodes. Only nodes which satisfy the predicate will be selected. Predicates follow the step they apply to, and use square brackets. /TEI/text/body/div means all the div nodes which are children of body. /TEI/text/body/div[@type='chapter'] means only those div nodes which are children of body and also have a type attribute with the value chapter.
XPath Predicates: some examples = all div nodes which have a direct child head element. = all div nodes which have a direct child head element which contains the text Scene. = the first div node in the document. = the last div node in the document.
XPath Predicates: Tasks (1)

Using the places.xml file here: http://www.wwp.northeastern.edu/outreach/seminars/uvic_xslt_2017/demos/xslt_intro/places.xml and the XPath console in oXygen, find the following information:

How many place entries are mapped as polygons? (Hint: a polygon location has more than 2 geo elements.) How many are single points? How many place entries contain external links (ref type="external")?
XPath Predicates: Tasks (1) answers

Using the places.xml file, and the XPath console in oXygen, find the following information:

How many place entries are mapped as polygons? (Hint: a polygon location has more than 2 geo elements.) (The answer is 77.) How many are single points? (The answer is 110.) How many place entries contain external links (ref type="external")? (The answer is 105.)
XPath Predicates can be chained = all scenes containing more than 200 lines. = all scenes in which Horatio speaks. = speeches by Hamlet which are the last speeches in their scene. Supplementary question: how would you find the last speech in the whole play? Hint: you can use the following:: axis.

The Hamlet file actually has lots of ab elements in speeches as well as l elements, so this line count stuff is not a true reflection of the length of speeches. It might be worth telling the students there's something wrong with it, and asking them to look at the XML source to see if they can figure out what it is. Then you could amend the first item in this slide, and some of the ones in the next slide, to account for this.

The Hamlet file actually has lots of ab elements in speeches as well as l elements, so this line count stuff is not a true reflection of the length of speeches. It might be worth telling the students there's something wrong with it, and asking them to look at the XML source to see if they can figure out what it is. Then you could amend the first item in this slide, and some of the ones in the next slide, to account for this.
XPath Predicates can be nested = all speeches which contain metrical lines which mention Ophelia. = all scenes in which Hamlet has more than 30 speeches. = speeches with three or more lines that mention "love". How does this differ from the XPath above? Under what circumstances would this difference matter?
XPath Predicates: Tasks (2)

Using the places.xml file, and the XPath console in <oXygen/>, find the following information:

How many place entries which are single points contain external links? How many place entries mention the name whose key value is kellett? How many place entries have a bibliography with more than two items?
XPath Predicates: Tasks (2) answer 1 How many place entries which are single points contain external links? (The answer is 58.)
XPath Predicates: Tasks (2) answer 2 How many place entries mention the name whose key value is kellett? (The answer is 9.)
XPath Predicates: Tasks (2) answer 3 How many place entries have a bibliography with more than two items? (The answer is 12.) Note: if we omit the [parent::listBibl] predicate, we will be counting bibl elements which appear outside the bibliography list, in the body of the explanatory text.