XPath

XPath is Go package provides selecting nodes from XML, HTML or other documents using XPath expression.

Implementation

• htmlquery - an XPath query package for HTML document

• xmlquery - an XPath query package for XML document.

• jsonquery - an XPath query package for JSON document

Supported Features

The basic XPath patterns.

The basic XPath patterns cover 90% of the cases that most stylesheets will need.

• node : Selects all child elements with nodeName of node.

• * : Selects all child elements.

• @attr : Selects the attribute attr.

• @* : Selects all attributes.

• node() : Matches an org.w3c.dom.Node.

• text() : Matches a org.w3c.dom.Text node.

• comment() : Matches a comment.

• . : Selects the current node.

• .. : Selects the parent of current node.

• / : Selects the document node.

• a[expr] : Select only those nodes matching a which also satisfy the expression expr.

• a[n] : Selects the nth matching node matching a When a filter's expression is a number, XPath selects based on position.

• a/b : For each node matching a, add the nodes matching b to the result.

• a//b : For each node matching a, add the descendant nodes matching b to the result.

• //b : Returns elements in the entire document matching b.

• a|b : All nodes matching a or b, union operation(not boolean or).

• (a, b, c) : Evaluates each of its operands and concatenates the resulting sequences, in order, into a single result sequence

• (a/b) : Selects all matches nodes as grouping set.

Node Axes

• child::* : The child axis selects children of the current node.

  • child::node(): Selects all the children of the context node.
  • child::text(): Selects all text node children of the context node.

• descendant::* : The descendant axis selects descendants of the current node. It is equivalent to '//'.

• descendant-or-self::* : Selects descendants including the current node.

• attribute::* : Selects attributes of the current element. It is equivalent to @*

• following-sibling::* : Selects nodes after the current node.

• preceding-sibling::* : Selects nodes before the current node.

• following::* : Selects the first matching node following in document order, excluding descendants.

• preceding::* : Selects the first matching node preceding in document order, excluding ancestors.

• parent::* : Selects the parent if it matches. The '..' pattern from the core is equivalent to 'parent::node()'.

• ancestor::* : Selects matching ancestors.

• ancestor-or-self::* : Selects ancestors including the current node.

• self::* : Selects the current node. '.' is equivalent to 'self::node()'.

Expressions

The gxpath supported three types: number, boolean, string.

• path : Selects nodes based on the path.

• a = b : Standard comparisons.

  • a = b : True if a equals b.
  • a != b : True if a is not equal to b.
  • a < b : True if a is less than b.
  • a <= b : True if a is less than or equal to b.
  • a > b : True if a is greater than b.
  • a >= b : True if a is greater than or equal to b.

• a + b : Arithmetic expressions.

  • - a Unary minus
  • a + b : Addition
  • a - b : Subtraction
  • a * b : Multiplication
  • a div b : Division
  • a mod b : Modulus (division remainder)

• a or b : Boolean or operation.

• a and b : Boolean and operation.

• (expr) : Parenthesized expressions.

• fun(arg1, ..., argn) : Function calls:

| Function | Supported | | ----------------------- | --------- | | boolean() | ✓ | | ceiling() | ✓ | | choose() | ✗ | | concat() | ✓ | | contains() | ✓ | | count() | ✓ | | current() | ✗ | | document() | ✗ | | element-available() | ✗ | | ends-with() | ✓ | | false() | ✓ | | floor() | ✓ | | format-number() | ✗ | | function-available() | ✗ | | generate-id() | ✗ | | id() | ✗ | | key() | ✗ | | lang() | ✗ | | last() | ✓ | | local-name() | ✓ | | lower-case()[^1] | ✓ | | matches() | ✓ | | name() | ✓ | | namespace-uri() | ✓ | | normalize-space() | ✓ | | not() | ✓ | | number() | ✓ | | position() | ✓ | | replace() | ✓ | | reverse() | ✓ | | round() | ✓ | | starts-with() | ✓ | | string() | ✓ | | string-join()[^1] | ✓ | | string-length() | ✓ | | substring() | ✓ | | substring-after() | ✓ | | substring-before() | ✓ | | sum() | ✓ | | system-property() | ✗ | | translate() | ✓ | | true() | ✓ | | unparsed-entity-url() | ✗ |

[^1]: XPath-2.0 expression