nltk.corpus.reader.xmldocs module

Corpus reader for corpora whose documents are xml files.

(note – not named ‘xml’ to avoid conflicting w/ standard xml package)

class nltk.corpus.reader.xmldocs.XMLCorpusReader

Bases: CorpusReader

Corpus reader for corpora whose documents are xml files.

Note that the XMLCorpusReader constructor does not take an encoding argument, because the unicode encoding is specified by the XML files themselves. See the XML specs for more info.

__init__(root, fileids, wrap_etree=False)

Parameters

• root (PathPointer or str) – A path pointer identifying the root directory for this corpus. If a string is specified, then it will be converted to a PathPointer automatically.

• fileids – A list of the files that make up this corpus. This list can either be specified explicitly, as a list of strings; or implicitly, as a regular expression over file paths. The absolute path for each file will be constructed by joining the reader’s root to each file name.

• encoding –

  The default unicode encoding for the files that make up the corpus. The value of encoding can be any of the following:

  • A string: encoding is the encoding name for all files.

  • A dictionary: encoding[file_id] is the encoding name for the file whose identifier is file_id. If file_id is not in encoding, then the file contents will be processed using non-unicode byte strings.

  • A list: encoding should be a list of (regexp, encoding) tuples. The encoding for a file whose identifier is file_id will be the encoding value for the first tuple whose regexp matches the file_id. If no tuple’s regexp matches the file_id, the file contents will be processed using non-unicode byte strings.

  • None: the file contents of all files will be processed using non-unicode byte strings.

• tagset – The name of the tagset used by this corpus, to be used for normalizing or converting the POS tags returned by the tagged_...() methods.

words(fileid=None)

Returns all of the words and punctuation symbols in the specified file that were in text nodes – ie, tags are ignored. Like the xml() method, fileid can only specify one file.

Returns

the given file’s text nodes as a list of words and punctuation symbols

Return type

list(str)

xml(fileid=None)

class nltk.corpus.reader.xmldocs.XMLCorpusView

Bases: StreamBackedCorpusView

A corpus view that selects out specified elements from an XML file, and provides a flat list-like interface for accessing them. (Note: XMLCorpusView is not used by XMLCorpusReader itself, but may be used by subclasses of XMLCorpusReader.)

Every XML corpus view has a “tag specification”, indicating what XML elements should be included in the view; and each (non-nested) element that matches this specification corresponds to one item in the view. Tag specifications are regular expressions over tag paths, where a tag path is a list of element tag names, separated by ‘/’, indicating the ancestry of the element. Some examples:

• 'foo': A top-level element whose tag is foo.

• 'foo/bar': An element whose tag is bar and whose parent is a top-level element whose tag is foo.

• '.*/foo': An element whose tag is foo, appearing anywhere in the xml tree.

• '.*/(foo|bar)': An wlement whose tag is foo or bar, appearing anywhere in the xml tree.

The view items are generated from the selected XML elements via the method handle_elt(). By default, this method returns the element as-is (i.e., as an ElementTree object); but it can be overridden, either via subclassing or via the elt_handler constructor parameter.

__init__(fileid, tagspec, elt_handler=None)

Create a new corpus view based on a specified XML file.

Note that the XMLCorpusView constructor does not take an encoding argument, because the unicode encoding is specified by the XML files themselves.

Parameters

• tagspec (str) – A tag specification, indicating what XML elements should be included in the view. Each non-nested element that matches this specification corresponds to one item in the view.

• elt_handler –

  A function used to transform each element to a value for the view. If no handler is specified, then self.handle_elt() is called, which returns the element as an ElementTree object. The signature of elt_handler is:

  elt_handler(elt, tagspec) -> value
  

handle_elt(elt, context)

Convert an element into an appropriate value for inclusion in the view. Unless overridden by a subclass or by the elt_handler constructor argument, this method simply returns elt.

Returns

The view value corresponding to elt.

Parameters

• elt (ElementTree) – The element that should be converted.

• context (str) – A string composed of element tags separated by forward slashes, indicating the XML context of the given element. For example, the string 'foo/bar/baz' indicates that the element is a baz element whose parent is a bar element and whose grandparent is a top-level foo element.

read_block(stream, tagspec=None, elt_handler=None)

Read from stream until we find at least one element that matches tagspec, and return the result of applying elt_handler to each element found.