Source code for pythainlp.tokenize.tcc_p

# -*- 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
#
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# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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"""
The implementation of tokenizer accorinding to Thai Character Clusters (TCCs)
rules purposed by `Theeramunkong et al. 2000. \
    <http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.59.2548>`_
and improve the rule that used in newmm

Credits:
    * TCC: Jakkrit TeCho
    * Grammar: Wittawat Jitkrittum (`link to the source file \
      <https://github.com/wittawatj/jtcc/blob/master/TCC.g>`_)
    * Python code: Korakot Chaovavanich
"""
import re
from typing import List, Set

_RE_TCC = (
    """\
เc็ck
เcctาะk
เccีtยะk
เccีtย(?=[เ-ไก-ฮ]|$)k
เcc็ck
เcิc์ck
เcิtck
เcีtยะ?k
เcืtอะ?k
เc[ิีุู]tย(?=[เ-ไก-ฮ]|$)k
เctา?ะ?k
cัtวะk
c[ัื]tc[ุิะ]?k
c[ิุู]์
c[ะ-ู]tk
cรรc์
c็
ct[ะาำ]?k
ck
แc็c
แcc์
แctะ
แcc็c
แccc์
โctะ
[เ-ไ]ct
ก็
อึ
หึ
""".replace(
        "k", "(cc?[dิ]?[์])?"
    )
    .replace("c", "[ก-ฮ]")
    .replace("t", "[่-๋]?")
    .replace("d", "อูอุ".replace("อ", ""))  # DSara: lower vowel
    .split()
)

_PAT_TCC = re.compile("|".join(_RE_TCC))


[docs]def tcc(text: str) -> str: """ TCC generator, generates Thai Character Clusters :param str text: text to be tokenized to character clusters :return: subwords (character clusters) :rtype: Iterator[str] """ if not text or not isinstance(text, str): return "" len_text = len(text) p = 0 while p < len_text: m = _PAT_TCC.match(text[p:]) if m: n = m.span()[1] else: n = 1 yield text[p : p + n] p += n
[docs]def tcc_pos(text: str) -> Set[int]: """ TCC positions :param str text: text to be tokenized to character clusters :return: list of the end position of subwords :rtype: set[int] """ if not text or not isinstance(text, str): return set() p_set = set() p = 0 for w in tcc(text): p += len(w) p_set.add(p) return p_set
[docs]def segment(text: str) -> List[str]: """ Subword segmentation :param str text: text to be tokenized to character clusters :return: list of subwords (character clusters), tokenized from the text :rtype: list[str] """ return list(tcc(text))