The XML Example Document
We will use the following XML document in the examples below.
<?xml version="1.0" encoding="ISO-8859-1"?> <bookstore> <book> <title lang="eng">Harry Potter</title> <price>29.99</price> </book> <book> <title lang="eng">Learning XML</title> <price>39.95</price> </book> </bookstore>
XPath Axes
An axis defines a node-set relative to the current node.
一条主线指定了一系列的节点和当前节点的关系
| AxisName |
Result |
| ancestor |
Selects all ancestors (parent, grandparent, etc.) of the current node 选择当前节点的所有的祖先，根，（父，父之父） |
| ancestor-or-self |
Selects all ancestors (parent, grandparent, etc.) of the current node and the current node itself 选择当前节点所有的祖节点和自己 |
| attribute |
Selects all attributes of the current node 选择当前节点的所有属性 |
| child |
Selects all children of the current node 选择当前节点的所有子节点 |
| descendant |
Selects all descendants (children, grandchildren, etc.) of the current node 选择当前节点的所有胄（子，子之子等） |
| descendant-or-self |
Selects all descendants (children, grandchildren, etc.) of the current node and the current node itself 选择当前节点的所有子节点和自己 |
| following |
Selects everything in the document after the closing tag of the current node 选择当前节点结束后的文档中的所有节点 |
| following-sibling |
Selects all siblings after the current node 选择当前节点后的所有同科节点 |
| namespace |
Selects all namespace nodes of the current node 选择当前节点的所有的名字空间 |
| parent |
Selects the parent of the current node 选择当前节点的所有父节点 |
| preceding |
Selects everything in the document that is before the start tag of the current node 选择文档中当前节点前的所有节点 |
| preceding-sibling |
Selects all siblings before the current node 选择当前节点前的所有同科节点 |
| self |
Selects the current node 选择当前节点 |
Location Path Expression位置表达式
A location path can be absolute or relative.
可以是绝对的也可以是相对的
An absolute location path starts with a slash ( / ) and a relative location path does not. In both cases the location path consists of one or more steps, each separated by a slash:
一个绝对的路径以＂／＂开始，两种表示式都有一级或多级构成，级用＂／＂分开
An absolute location path:
/step/step/...
A relative location path:
step/step/...
Each step is evaluated against the nodes in the current node-set.
每一级都是根据当前节点的在节点集的位置来执行的
A step consists of:级构成：
The syntax for a location step is:语法
axisname::nodetest[predicate]
Examples:
| Example |
Result |
| child::book |
Selects all book nodes that are children of the current node 选择当前节点的所有的book节点 |
| attribute::lang |
Selects the lang attribute of the current node 选择当前节点的lang 属性 |
| child::* |
Selects all children of the current node 选择当前节点的所有子节点 |
| attribute::* |
Selects all attributes of the current node 选择当前节点的所有属性 |
| child::text() |
Selects all text child nodes of the current node 选择当前节点的所有文本子节点 |
| child::node() |
Selects all child nodes of the current node 选择当前节点的所有子节点 |
| descendant::book |
Selects all book descendants of the current node 选择当节点的所有book胄 |
| ancestor::book |
Selects all book ancestors of the current node 选择当前节点的所有book节点的祖，根 |
| ancestor-or-self::book |
Selects all book ancestors of the current node - and the current as well if it is a book node 选择当前节点的book元素的根节点或它自己（如果它也是一个book节点的话） |
| child::*/child::price |
Selects all price grandchildren of the current node |
此内容由惯性聚合(RSS阅读器)自动聚合整理，仅供阅读参考。 原文来自 — 版权归原作者所有。