nltk.corpus.reader.ConllCorpusReader

class nltk.corpus.reader.ConllCorpusReader

Bases: CorpusReader

A corpus reader for CoNLL-style files. These files consist of a series of sentences, separated by blank lines. Each sentence is encoded using a table (or “grid”) of values, where each line corresponds to a single word, and each column corresponds to an annotation type. The set of columns used by CoNLL-style files can vary from corpus to corpus; the ConllCorpusReader constructor therefore takes an argument, columntypes, which is used to specify the columns that are used by a given corpus. By default columns are split by consecutive whitespaces, with the separator argument you can set a string to split by (e.g. ' ').

@todo: Add support for reading from corpora where different

parallel files contain different columns.

@todo: Possibly add caching of the grid corpus view? This would

allow the same grid view to be used by different data access methods (eg words() and parsed_sents() could both share the same grid corpus view object).

@todo: Better support for -DOCSTART-. Currently, we just ignore

it, but it could be used to define methods that retrieve a document at a time (eg parsed_documents()).

WORDS = 'words'

column type for words

POS = 'pos'

column type for part-of-speech tags

TREE = 'tree'

column type for parse trees

CHUNK = 'chunk'

column type for chunk structures

NE = 'ne'

column type for named entities

SRL = 'srl'

column type for semantic role labels

IGNORE = 'ignore'

column type for column that should be ignored

COLUMN_TYPES = ('words', 'pos', 'tree', 'chunk', 'ne', 'srl', 'ignore')

A list of all column types supported by the conll corpus reader.

__init__(root, fileids, columntypes, chunk_types=None, root_label='S', pos_in_tree=False, srl_includes_roleset=True, encoding='utf8', tree_class=<class 'nltk.tree.tree.Tree'>, tagset=None, separator=None)

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(fileids=None)

sents(fileids=None)

tagged_words(fileids=None, tagset=None)

tagged_sents(fileids=None, tagset=None)

chunked_words(fileids=None, chunk_types=None, tagset=None)

chunked_sents(fileids=None, chunk_types=None, tagset=None)

parsed_sents(fileids=None, pos_in_tree=None, tagset=None)

srl_spans(fileids=None)

srl_instances(fileids=None, pos_in_tree=None, flatten=True)

iob_words(fileids=None, tagset=None)

Returns

a list of word/tag/IOB tuples

Return type

list(tuple)

Parameters

fileids (None or str or list) – the list of fileids that make up this corpus

iob_sents(fileids=None, tagset=None)

Returns

a list of lists of word/tag/IOB tuples

Return type

list(list)

Parameters

fileids (None or str or list) – the list of fileids that make up this corpus

abspath(fileid)

Return the absolute path for the given file.

Parameters

fileid (str) – The file identifier for the file whose path should be returned.

Return type

PathPointer

abspaths(fileids=None, include_encoding=False, include_fileid=False)

Return a list of the absolute paths for all fileids in this corpus; or for the given list of fileids, if specified.

Parameters

• fileids (None or str or list) – Specifies the set of fileids for which paths should be returned. Can be None, for all fileids; a list of file identifiers, for a specified set of fileids; or a single file identifier, for a single file. Note that the return value is always a list of paths, even if fileids is a single file identifier.

• include_encoding – If true, then return a list of (path_pointer, encoding) tuples.

Return type

list(PathPointer)

citation()

Return the contents of the corpus citation.bib file, if it exists.

encoding(file)

Return the unicode encoding for the given corpus file, if known. If the encoding is unknown, or if the given file should be processed using byte strings (str), then return None.

ensure_loaded()

Load this corpus (if it has not already been loaded). This is used by LazyCorpusLoader as a simple method that can be used to make sure a corpus is loaded – e.g., in case a user wants to do help(some_corpus).

fileids()

Return a list of file identifiers for the fileids that make up this corpus.

license()

Return the contents of the corpus LICENSE file, if it exists.

open(file)

Return an open stream that can be used to read the given file. If the file’s encoding is not None, then the stream will automatically decode the file’s contents into unicode.

Parameters

file – The file identifier of the file to read.

raw(fileids=None)

Parameters

fileids – A list specifying the fileids that should be used.

Returns

the given file(s) as a single string.

Return type

str

readme()

Return the contents of the corpus README file, if it exists.

property root

The directory where this corpus is stored.

Type

PathPointer