Source code for textattack.transformations.word_swaps.word_swap_random_character_insertion

"""
Word Swap by Random Character Insertion
------------------------------------------------

"""
import numpy as np

# from textattack.shared import utils
from .word_swap import WordSwap


[docs]class WordSwapRandomCharacterInsertion(WordSwap): """Transforms an input by inserting a random character. random_one (bool): Whether to return a single word with a random character deleted. If not, returns all possible options. skip_first_char (bool): Whether to disregard inserting as the first character. skip_last_char (bool): Whether to disregard inserting as the last character. >>> from textattack.transformations import WordSwapRandomCharacterInsertion >>> from textattack.augmentation import Augmenter >>> transformation = WordSwapRandomCharacterInsertion() >>> augmenter = Augmenter(transformation=transformation) >>> s = 'I am fabulous.' >>> augmenter.augment(s) """ def __init__( self, random_one=True, skip_first_char=False, skip_last_char=False, **kwargs ): super().__init__(**kwargs) self.random_one = random_one self.skip_first_char = skip_first_char self.skip_last_char = skip_last_char def _get_replacement_words(self, word): """Returns returns a list containing all possible words with 1 random character inserted.""" if len(word) <= 1: return [] candidate_words = [] start_idx = 1 if self.skip_first_char else 0 end_idx = (len(word) - 1) if self.skip_last_char else len(word) if start_idx >= end_idx: return [] if self.random_one: i = np.random.randint(start_idx, end_idx) candidate_word = word[:i] + self._get_random_letter() + word[i:] candidate_words.append(candidate_word) else: for i in range(start_idx, end_idx): candidate_word = word[:i] + self._get_random_letter() + word[i:] candidate_words.append(candidate_word) return candidate_words @property def deterministic(self): return not self.random_one
[docs] def extra_repr_keys(self): return super().extra_repr_keys() + ["random_one"]