API reference

parsel.csstranslator

class parsel.csstranslator.GenericTranslator

Bases: TranslatorMixin, GenericTranslator

css_to_xpath(css: str, prefix: str = 'descendant-or-self::') → str

Translate a group of selectors to XPath.

Pseudo-elements are not supported here since XPath only knows about “real” elements.

Parameters:

• css – A group of selectors as a string.

• prefix – This string is prepended to the XPath expression for each selector. The default makes selectors scoped to the context node’s subtree.

Raises:

SelectorSyntaxError on invalid selectors, ExpressionError on unknown/unsupported selectors, including pseudo-elements.

Returns:

The equivalent XPath 1.0 expression as a string.

class parsel.csstranslator.HTMLTranslator(xhtml: bool = False)

Bases: TranslatorMixin, HTMLTranslator

css_to_xpath(css: str, prefix: str = 'descendant-or-self::') → str

Translate a group of selectors to XPath.

Pseudo-elements are not supported here since XPath only knows about “real” elements.

Parameters:

• css – A group of selectors as a string.

• prefix – This string is prepended to the XPath expression for each selector. The default makes selectors scoped to the context node’s subtree.

Raises:

SelectorSyntaxError on invalid selectors, ExpressionError on unknown/unsupported selectors, including pseudo-elements.

Returns:

The equivalent XPath 1.0 expression as a string.

class parsel.csstranslator.TranslatorMixin

Bases: object

This mixin adds support to CSS pseudo elements via dynamic dispatch.

Currently supported pseudo-elements are ::text and ::attr(ATTR_NAME).

xpath_attr_functional_pseudo_element(xpath: XPathExpr, function: FunctionalPseudoElement) → XPathExpr

Support selecting attribute values using ::attr() pseudo-element

xpath_element(selector: Element) → XPathExpr

xpath_pseudo_element(xpath: XPathExpr, pseudo_element: FunctionalPseudoElement | str) → XPathExpr

Dispatch method that transforms XPath to support pseudo-element

xpath_text_simple_pseudo_element(xpath: XPathExpr) → XPathExpr

Support selecting text nodes using ::text pseudo-element

class parsel.csstranslator.TranslatorProtocol(*args, **kwargs)

Bases: Protocol

css_to_xpath(css: str, prefix: str = Ellipsis) → str

xpath_element(selector: Element) → XPathExpr

class parsel.csstranslator.XPathExpr(path: str = '', element: str = '*', condition: str = '', star_prefix: bool = False)

Bases: XPathExpr

attribute: str | None = None

classmethod from_xpath(xpath: OriginalXPathExpr, textnode: bool = False, attribute: str | None = None) → Self

join(combiner: str, other: OriginalXPathExpr, *args: Any, **kwargs: Any) → Self

textnode: bool = False

parsel.csstranslator.css2xpath(query: str) → str

Return translated XPath version of a given CSS query

parsel.selector

XPath and JMESPath selectors based on the lxml and jmespath Python packages.

class parsel.selector.CTGroupValue

Bases: TypedDict

exception parsel.selector.CannotDropElementWithoutParent

Bases: CannotRemoveElementWithoutParent

exception parsel.selector.CannotRemoveElementWithoutParent

Bases: Exception

exception parsel.selector.CannotRemoveElementWithoutRoot

Bases: Exception

class parsel.selector.SafeXMLParser(*args: Any, **kwargs: Any)

Bases: XMLParser

class parsel.selector.Selector(text: str | None = None, type: str | None = None, body: bytes | bytearray = b'', encoding: str = 'utf-8', namespaces: Mapping[str, str] | None = None, root: Any | None = <object object>, base_url: str | None = None, _expr: str | None = None, huge_tree: bool = True)

Bases: object

Wrapper for input data in HTML, JSON, or XML format, that allows selecting parts of it using selection expressions.

You can write selection expressions in CSS or XPath for HTML and XML inputs, or in JMESPath for JSON inputs.

text is an str object.

body is a bytes object. It can be used together with the encoding argument instead of the text argument.

type defines the selector type. It can be "html" (default), "json", or "xml".

base_url allows setting a URL for the document. This is needed when looking up external entities with relative paths. See the documentation for lxml.etree.fromstring() for more information.

huge_tree controls the lxml/libxml2 feature that forbids parsing certain large documents to protect from possible memory exhaustion. The argument is True by default if the installed lxml version supports it, which disables the protection to allow parsing such documents. Set it to False if you want to enable the protection. See this lxml FAQ entry for more information.

property attrib: dict[str, str]

Return the attributes dictionary for underlying element. For JSON selectors, return an empty dict.

body

css(query: str) → SelectorList[Self]

Apply the given CSS selector and return a SelectorList instance.

query is a string containing the CSS selector to apply.

In the background, CSS queries are translated into XPath queries using cssselect library and run .xpath() method.

drop() → None

Drop matched nodes from the parent element.

extract() → Any

Serialize and return the matched nodes.

For HTML and XML, the result is always a string, and percent-encoded content is unquoted.

get() → Any

Serialize and return the matched nodes.

For HTML and XML, the result is always a string, and percent-encoded content is unquoted.

getall() → list[str]

Serialize and return the matched node in a 1-element list of strings.

jmespath(query: str, **kwargs: Any) → SelectorList[Self]

Find objects matching the JMESPath query and return the result as a SelectorList instance with all elements flattened. List elements implement Selector interface too.

query is a string containing the JMESPath query to apply.

Any additional named arguments are passed to the underlying jmespath.search call, e.g.:

selector.jmespath('author.name', options=jmespath.Options(dict_cls=collections.OrderedDict))

namespaces

re(regex: str | Pattern[str], replace_entities: bool = True) → list[str]

Apply the given regex and return a list of strings with the matches.

regex can be either a compiled regular expression or a string which will be compiled to a regular expression using re.compile(regex).

By default, character entity references are replaced by their corresponding character (except for & and <). Passing replace_entities as False switches off these replacements.

re_first(regex: str | Pattern[str], default: None = None, replace_entities: bool = True) → str | None

re_first(regex: str | Pattern[str], default: str, replace_entities: bool = True) → str

Apply the given regex and return the first string which matches. If there is no match, return the default value (None if the argument is not provided).

By default, character entity references are replaced by their corresponding character (except for & and <). Passing replace_entities as False switches off these replacements.

register_namespace(prefix: str, uri: str) → None

Register the given namespace to be used in this Selector. Without registering namespaces you can’t select or extract data from non-standard namespaces. See Working on XML (and namespaces).

remove_namespaces() → None

Remove all namespaces, allowing to traverse the document using namespace-less xpaths. See Removing namespaces. For JSON selectors, this method does nothing.

root: Any

selectorlist_cls

alias of SelectorList[Selector]

type

xpath(query: str, namespaces: Mapping[str, str] | None = None, **kwargs: Any) → SelectorList[Self]

Find nodes matching the xpath query and return the result as a SelectorList instance with all elements flattened. List elements implement Selector interface too.

query is a string containing the XPATH query to apply.

namespaces is an optional prefix: namespace-uri mapping (dict) for additional prefixes to those registered with register_namespace(prefix, uri). Contrary to register_namespace(), these prefixes are not saved for future calls.

Any additional named arguments can be used to pass values for XPath variables in the XPath expression, e.g.:

selector.xpath('//a[href=$url]', url="http://www.example.com")

class parsel.selector.SelectorList(iterable=(), /)

Bases: list[_SelectorType]

The SelectorList class is a subclass of the builtin list class, which provides a few additional methods.

property attrib: Mapping[str, str]

Return the attributes dictionary for the first element. If the list is empty, return an empty dict.

css(query: str) → SelectorList[_SelectorType]

Call the .css() method for each element in this list and return their results flattened as another SelectorList.

query is the same argument as the one in Selector.css()

drop() → None

Drop matched nodes from the parent for each element in this list.

extract() → list[str]

Call the .get() method for each element is this list and return their results flattened, as a list of strings.

extract_first(default: str | None = None) → Any

Return the result of .get() for the first element in this list. If the list is empty, return the default value.

get(default: None = None) → str | None

get(default: str) → str

Return the result of .get() for the first element in this list. If the list is empty, return the default value.

getall() → list[str]

Call the .get() method for each element is this list and return their results flattened, as a list of strings.

jmespath(query: str, **kwargs: Any) → SelectorList[_SelectorType]

Call the .jmespath() method for each element in this list and return their results flattened as another SelectorList.

query is the same argument as the one in Selector.jmespath().

Any additional named arguments are passed to the underlying jmespath.search call, e.g.:

selector.jmespath('author.name', options=jmespath.Options(dict_cls=collections.OrderedDict))

re(regex: str | Pattern[str], replace_entities: bool = True) → list[str]

Call the .re() method for each element in this list and return their results flattened, as a list of strings.

By default, character entity references are replaced by their corresponding character (except for & and <. Passing replace_entities as False switches off these replacements.

re_first(regex: str | Pattern[str], default: None = None, replace_entities: bool = True) → str | None

re_first(regex: str | Pattern[str], default: str, replace_entities: bool = True) → str

Call the .re() method for the first element in this list and return the result in an string. If the list is empty or the regex doesn’t match anything, return the default value (None if the argument is not provided).

By default, character entity references are replaced by their corresponding character (except for & and <. Passing replace_entities as False switches off these replacements.

xpath(xpath: str, namespaces: Mapping[str, str] | None = None, **kwargs: Any) → SelectorList[_SelectorType]

Call the .xpath() method for each element in this list and return their results flattened as another SelectorList.

xpath is the same argument as the one in Selector.xpath()

namespaces is an optional prefix: namespace-uri mapping (dict) for additional prefixes to those registered with register_namespace(prefix, uri). Contrary to register_namespace(), these prefixes are not saved for future calls.

Any additional named arguments can be used to pass values for XPath variables in the XPath expression, e.g.:

selector.xpath('//a[href=$url]', url="http://www.example.com")

parsel.selector.create_root_node(text: str, parser_cls: type[XMLParser | HTMLParser], base_url: str | None = None, huge_tree: bool = True, body: bytes = b'', encoding: str = 'utf-8') → _Element

Create root node for text using given parser class.

parsel.utils

parsel.utils.extract_regex(regex: str | Pattern[str], text: str, replace_entities: bool = True) → list[str]

Extract a list of strings from the given text/encoding using the following policies: * if the regex contains a named group called “extract” that will be returned * if the regex contains multiple numbered groups, all those will be returned (flattened) * if the regex doesn’t contain any group the entire regex matching is returned

parsel.utils.flatten(sequence) → list

Returns a single, flat list which contains all elements retrieved from the sequence and all recursively contained sub-sequences (iterables). Examples: >>> [1, 2, [3,4], (5,6)] [1, 2, [3, 4], (5, 6)] >>> flatten([[[1,2,3], (42,None)], [4,5], [6], 7, (8,9,10)]) [1, 2, 3, 42, None, 4, 5, 6, 7, 8, 9, 10] >>> flatten([“foo”, “bar”]) [‘foo’, ‘bar’] >>> flatten([“foo”, [“baz”, 42], “bar”]) [‘foo’, ‘baz’, 42, ‘bar’]

parsel.utils.iflatten(sequence) → Iterator

Similar to .flatten(), but returns iterator instead Examples: >>> list(iflatten([[1, 2], (3, 4)])) [1, 2, 3, 4]

parsel.utils.shorten(text: str, width: int, suffix: str = '...') → str

Truncate the given text to fit in the given width.