XPath- asse
Die XML-voorbeelddokument
Ons sal die volgende XML-dokument in die voorbeelde hieronder gebruik.
<?xml version="1.0" encoding="UTF-8"?>
<bookstore>
<book>
<title lang="en">Harry Potter</title>
<price>29.99</price>
</book>
<book>
<title lang="en">Learning XML</title>
<price>39.95</price>
</book>
</bookstore>
XPath-asse
'n As verteenwoordig 'n verhouding met die konteks (huidige) nodus, en word gebruik om nodusse relatief tot daardie nodus op die boom op te spoor.
| AxisName | Result |
|---|---|
| ancestor | Selects all ancestors (parent, grandparent, etc.) of the current node |
| ancestor-or-self | Selects all ancestors (parent, grandparent, etc.) of the current node and the current node itself |
| attribute | Selects all attributes of the current node |
| child | Selects all children of the current node |
| descendant | Selects all descendants (children, grandchildren, etc.) of the current node |
| descendant-or-self | Selects all descendants (children, grandchildren, etc.) of the current node and the current node itself |
| following | Selects everything in the document after the closing tag of the current node |
| following-sibling | Selects all siblings after the current node |
| namespace | Selects all namespace nodes of the current node |
| parent | Selects the parent of the current node |
| preceding | Selects all nodes that appear before the current node in the document, except ancestors, attribute nodes and namespace nodes |
| preceding-sibling | Selects all siblings before the current node |
| self | Selects the current node |
Ligging Pad Uitdrukking
'n Liggingspad kan absoluut of relatief wees.
'n Absolute liggingpad begin met 'n skuinsstreep ( / ) en 'n relatiewe liggingpad nie. In beide gevalle bestaan die liggingpad uit een of meer stappe, elk geskei deur 'n skuinsstreep:
An absolute location path:
/step/step/...
A relative location path:
step/step/...
Elke stap word teen die nodusse in die huidige nodusstel geëvalueer.
'n Stap bestaan uit:
- 'n as (definieer die boomverwantskap tussen die geselekteerde nodusse en die huidige nodus)
- 'n nodustoets (identifiseer 'n nodus binne 'n as)
- nul of meer predikate (om die geselekteerde nodusstel verder te verfyn)
Die sintaksis vir 'n liggingstap is:
axisname::nodetest[predicate]
Voorbeelde
| Example | Result |
|---|---|
| child::book | Selects all book nodes that are children of the current node |
| attribute::lang | Selects the lang attribute of the current node |
| child::* | Selects all element children of the current node |
| attribute::* | Selects all attributes of the current node |
| child::text() | Selects all text node children of the current node |
| child::node() | Selects all children of the current node |
| descendant::book | Selects all book descendants of the current node |
| ancestor::book | Selects all book ancestors of the current node |
| ancestor-or-self::book | Selects all book ancestors of the current node - and the current as well if it is a book node |
| child::*/child::price | Selects all price grandchildren of the current node |