xpath.Expression
¶
The xpath.Expression
class represents a valid, compiled xpath expression.
It can be instantiated with the xpath.Expression.compile()
classmethod.
The same xpath.Expression
can be used for multiple executions with different xpath.RuntimeOptions
.
There is also a utility function xpath.compile()
that can be used to create an xpath.Expression
.
>>> session = Session()
>>> compile_options = CompileOptions(session)
>>> expr, log = Expression.compile('//*', compile_options)
>>> if expr is None:
>>> raise Exception("Error creating xpath expression", log)
>>> runtime_options = RuntimeOptions(session)
>>> runtime_options.initial_context = NodeItem.create_from_instance(xml.Instance.create_from_buffer(b'<?xml version="1.0"?><foo><bar>baz</bar></foo>')[0], session)
>>> seq, log = expr.execute(runtime_options)
>>> if seq is None:
>>> raise Exception("Error executing xpath expression", log)
>>> for i in seq:
>>> print(i.informationItem().local_name)
Base class: xpath.Executable
-> xpath.Module
- class xpath.Expression¶
Class methods¶
- classmethod xpath.Expression.compile(type cls, unicode text, CompileOptions options)¶
Compiles a new
xpath.Expression
from the provided expression text andxpath.CompileOptions
. This involves syntax checking, building of AST, initializing of static context components and static-analysis. In case of a syntax or a static error, thexpath.Expression
is None and the xml.ErrorLog contains the error(s).Returns: (
xpath.Expression
, xml.ErrorLog)>>> s = Session() >>> expr, log = Expression.compile('year-from-date(current-date()) ge 2018', CompileOptions(s)) >>> if expr None: >>> print(log) >>> else: >>> print('success') True
Attributes¶
- xpath.Module.location
- xpath.Executable.referenced_modules
- xpath.Module.schema
- xpath.Module.strip_input_type_annotations
- xpath.Module.whitespace_handler
Methods¶
- xpath.Expression.execute(RuntimeOptions options)¶
Execute the compiled
xpath.Expression
with the providedxpath.RuntimeOptions
. In case of a runtime error the returnedxpath.Sequence
is None and the xml.ErrorLog contains the error.Returns: (
xpath.Sequence
, xml.ErrorLog)>>> s = Session() >>> expr, log = Expression.compile('year-from-date(current-date()) ge 2018', CompileOptions(s)) >>> seq, log = expr.execute(RuntimeOptions(s)) >>> seq[0].anySimpleType().value True
- xpath.Module.load_xml_document(unicode uri, f)
Special methods¶
__eq__, __ge__, __gt__, __le__, __lt__, __ne__