Source code for textattack.transformations.word_insertions.word_insertion

"""
WordInsertion Class
-------------------------------
Word Insertion transformations act by inserting a new word at a specific word index.
For example, if we insert "new" in position 3 in the text "I like the movie", we get "I like the new movie".
Subclasses can implement the abstract ``WordInsertion`` class by overriding ``self._get_new_words``.
"""
from textattack.transformations import Transformation


[docs]class WordInsertion(Transformation): """A base class for word insertions.""" def _get_new_words(self, current_text, index): """Returns a set of new words we can insert at position `index` of `current_text` Args: current_text (AttackedText): Current text to modify. index (int): Position in which to insert a new word Returns: list[str]: List of new words to insert. """ raise NotImplementedError() def _get_transformations(self, current_text, indices_to_modify): """ Return a set of transformed texts obtained by insertion a new word in `indices_to_modify` Args: current_text (AttackedText): Current text to modify. indices_to_modify (list[int]): List of positions in which to insert a new word. Returns: list[AttackedText]: List of transformed texts """ transformed_texts = [] for i in indices_to_modify: new_words = self._get_new_words(current_text, i) new_transformted_texts = [] for w in new_words: new_transformted_texts.append( current_text.insert_text_before_word_index(i, w) ) transformed_texts.extend(new_transformted_texts) return transformed_texts