# -*- coding: utf-8 -*-
# Copyright (C) 2016-2023 PyThaiNLP Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from typing import List
import numpy as np
THAI_CHARACTERS_WITHOUT_SHIFT = [
"ผปแอิืทมใฝ",
"ฟหกดเ้่าสวง",
"ๆไำพะัีรนยบลฃ",
"ๅ/_ภถุึคตจขช",
]
THAI_CHARACTERS_WITH_SHIFT = [
"()ฉฮฺ์?ฒฬฦ",
"ฤฆฏโฌ็๋ษศซ.",
'๐"ฎฑธํ๊ณฯญฐ,',
"+๑๒๓๔ู฿๕๖๗๘๙",
]
ENGLISH_CHARACTERS_WITHOUT_SHIFT = [
"1234567890-=",
"qwertyuiop[]\\",
"asdfghjkl;'",
"zxcvbnm,./",
]
ENGLISH_CHARACTERS_WITH_SHIFT = [
"!@#$%^&*()_+",
"QWERTYUIOP{}|",
'ASDFGHJKL:"',
"ZXCVBNM<>?",
]
ALL_CHARACTERS = [
THAI_CHARACTERS_WITHOUT_SHIFT + THAI_CHARACTERS_WITH_SHIFT,
ENGLISH_CHARACTERS_WITHOUT_SHIFT + ENGLISH_CHARACTERS_WITH_SHIFT,
]
def search_location_of_character(char: str):
for language_ix in [0, 1]:
for ix, row in enumerate(ALL_CHARACTERS[language_ix]):
if char in row:
return (language_ix, ix // 4, ix % 4, row.index(char))
def find_neighbour_locations(
loc: tuple,
char: str,
kernel: List = [(-1, -1), (-1, 0), (1, 1), (0, 1), (0, -1), (1, 0)],
):
language_ix, is_shift, row, pos = loc
valid_neighbours = []
for kr, ks in kernel:
_row, _pos = row + kr, pos + ks
if 0 <= _row <= 3 and 0 <= _pos <= len(
ALL_CHARACTERS[language_ix][is_shift * 4 + _row]
):
valid_neighbours.append((language_ix, is_shift, _row, _pos, char))
return valid_neighbours
def find_misspell_candidates(char: str, verbose: bool = False):
loc = search_location_of_character(char)
if loc is None:
return None
valid_neighbours = find_neighbour_locations(loc, char)
chars = []
printing_locations = ["▐"] * 3 + [char] + ["▐"] * 3
for language_ix, is_shift, row, pos, char in valid_neighbours:
try:
char = ALL_CHARACTERS[language_ix][is_shift * 4 + row][pos]
chars.append(char)
kernel = (row - loc[1], pos - loc[2])
if kernel == (-1, -1):
ix = 5
elif kernel == (-1, 0):
ix = 6
elif kernel[0] == 0:
ix = 3 + kernel[1]
elif kernel == (1, 0):
ix = 0
elif kernel == (1, 1):
ix = 1
else:
continue
printing_locations[ix] = char
except IndexError as e:
continue
except Exception as e:
print("Something wrong with: ", char)
raise e
return chars
[docs]def misspell(sentence: str, ratio: float = 0.05):
"""
Simulate some mispellings for the input sentence.
The number of mispelled locations is governed by ratio.
:params str sentence: sentence to be mispelled
:params float ratio: number of misspells per 100 chars. Defaults to 0.5.
:return: sentence containing some misspelled
:rtype: str
:Example:
::
from pythainlp.tools.misspell import misspell
sentence = "ภาษาไทยปรากฏครั้งแรกในพุทธศักราช 1826"
misspell(sent, ratio=0.1)
# output:
ภาษาไทยปรากฏครั้งแรกในกุทธศักราช 1727
"""
num_misspells = np.floor(len(sentence) * ratio).astype(int)
positions = np.random.choice(
len(sentence), size=num_misspells, replace=False
)
# convert strings to array of characters
misspelled = list(sentence)
for pos in positions:
potential_candidates = find_misspell_candidates(sentence[pos])
if potential_candidates is None:
continue
candidate = np.random.choice(potential_candidates)
misspelled[pos] = candidate
return "".join(misspelled)