For loading new Conll objects from a file or string, prefer the load module which provides the main entry points for parsing CoNLL.

This module represents a CoNLL file, i.e. a collection of CoNLL annotated sentences. Like other collections in python, Conll objects can be indexed, sliced, iterated, etc (specifically it implements the MutableSequence contract). Conll objects are Conllable, so then can be converted into a CoNLL string or they can be written to file directly with the write method.


Defines the Conll type and the associated parsing and output logic.

class pyconll.unit.conll.Conll(it: Iterable[str])[source]

The abstraction for a CoNLL-U file. A CoNLL-U file is more or less just a collection of sentences in order. These sentences are accessed by numeric index. Note that sentences must be separated by whitespace. CoNLL-U also specifies that the file must end in a new line but that requirement is relaxed here in parsing.

__contains__(other: object) → bool[source]

Check if the Conll object has this sentence.


other – The sentence to check for.


True if this Sentence is exactly in the Conll object. False, otherwise.

__delitem__(key: Union[int, slice]) → None[source]

Delete the Sentence corresponding with the given key.


key – The info to get the Sentence to delete. Can be the integer position in the file, or a slice.

__getitem__(key: int)pyconll.unit.sentence.Sentence[source]
__getitem__(key: slice)Conll

Index a sentence by key value.


key – The key to index the sentence by. This key can either be a numeric key, or a slice.


The corresponding sentence if the key is an int or the sentences if the key is a slice in the form of another Conll object.


TypeError – If the key is not an integer or slice.

__init__(it: Iterable[str]) → None[source]

Create a CoNLL-U file collection of sentences.


it – An iterator of the lines of the CoNLL-U file.


ParseError – If there is an error constructing the sentences in the iterator.

__iter__() → Iterator[pyconll.unit.sentence.Sentence][source]

Allows for iteration over every sentence in the CoNLL-U file.


An iterator over the sentences in this Conll object.

__len__() → int[source]

Returns the number of sentences in the CoNLL-U file.


The size of the CoNLL-U file in sentences.

__setitem__(key: int, sent: pyconll.unit.sentence.Sentence) → None[source]
__setitem__(key: slice, sents: Iterable[pyconll.unit.sentence.Sentence]) → None

Set the given location to the Sentence.

  • key – The location in the Conll file to set to the given sentence. This accepts integer or slice keys and accepts negative indexing.

  • item – The item to insert. This can be an individual sentence, or another Conll object.

conll() → str[source]

Output the Conll object to a CoNLL-U formatted string.


The CoNLL-U object as a string. This string will end in a newline.


FormatError – If there are issues converting the sentences to the CoNLL format.

insert(index: int, value: pyconll.unit.sentence.Sentence) → None[source]

Insert the given sentence into the given location.

This function behaves in the same way as python lists insert.

  • index – The numeric index to insert the sentence into.

  • value – The sentence to insert.

write(writable: Any) → None[source]

Write the Conll object to something that is writable.

For file writing, this method is more efficient than calling conll then writing since no string of the entire Conll object is created. The output includes a final newline as detailed in the CoNLL-U specification.


writable – The writable object such as a file. Must have a write method.