Python常用功能函数系列总结（二）

 本节目录

• 常用函数一：sel文件转换

• 常用函数二：refwork文件转换

• 常用函数三：xml文档解析

• 常用函数四：文本分词

常用函数一：sel文件转换

    sel是种特殊的文件格式，具体应用场景的话可以在搜狗细胞词库中看到，经常在做文本处理，分词的时候需要一些词典，那么搜狗细胞词库中的一些相关词库就会被使用，而这种sel文件格式不能直接使用，需要进行转换，转换成txt文件之后就可以去做进一步使用了，转换的代码是从网上找到，我自己也是用过多次，使用的时候可以直接拿来用。

# -*- coding:utf-8 -*-
"""
@author:Zhang Yafei
@time: 2019/12/26
Description: scel 文件格式转换
"""
import struct
import os

# 搜狗的scel词库就是保存的文本的unicode编码，每两个字节一个字符（中文汉字或者英文字母）
# 找出其每部分的偏移位置即可
# 主要两部分
# 1.全局拼音表，貌似是所有的拼音组合，字典序
#       格式为(index,len,pinyin)的列表
#       index: 两个字节的整数 代表这个拼音的索引
#       len: 两个字节的整数 拼音的字节长度
#       pinyin: 当前的拼音，每个字符两个字节，总长len
#
# 2.汉语词组表
#       格式为(same,py_table_len,py_table,{word_len,word,ext_len,ext})的一个列表
#       same: 两个字节 整数 同音词数量
#       py_table_len:  两个字节 整数
#       py_table: 整数列表，每个整数两个字节,每个整数代表一个拼音的索引
#
#       word_len:两个字节 整数 代表中文词组字节数长度
#       word: 中文词组,每个中文汉字两个字节，总长度word_len
#       ext_len: 两个字节 整数 代表扩展信息的长度，好像都是10
#       ext: 扩展信息 前两个字节是一个整数(不知道是不是词频) 后八个字节全是0
#
#      {word_len,word,ext_len,ext} 一共重复same次 同音词 相同拼音表


# 拼音表偏移，
startPy = 0x1540;

# 汉语词组表偏移
startChinese = 0x2628;

# 全局拼音表
GPy_Table = {}

# 解析结果
# 元组(词频,拼音,中文词组)的列表
GTable = []


# 原始字节码转为字符串
def byte2str(data):
    pos = 0
    str = ''
    while pos < len(data):
        c = chr(struct.unpack('H', bytes([data[pos], data[pos + 1]]))[0])
        if c != chr(0):
            str += c
        pos += 2
    return str


# 获取拼音表
def getPyTable(data):
    data = data[4:]
    pos = 0
    while pos < len(data):
        index = struct.unpack('H', bytes([data[pos], data[pos + 1]]))[0]
        pos += 2
        lenPy = struct.unpack('H', bytes([data[pos], data[pos + 1]]))[0]
        pos += 2
        py = byte2str(data[pos:pos + lenPy])

        GPy_Table[index] = py
        pos += lenPy


# 获取一个词组的拼音
def getWordPy(data):
    pos = 0
    ret = ''
    while pos < len(data):
        index = struct.unpack('H', bytes([data[pos], data[pos + 1]]))[0]
        ret += GPy_Table[index]
        pos += 2
    return ret


# 读取中文表
def getChinese(data):
    pos = 0
    while pos < len(data):
        # 同音词数量
        same = struct.unpack('H', bytes([data[pos], data[pos + 1]]))[0]

        # 拼音索引表长度
        pos += 2
        py_table_len = struct.unpack('H', bytes([data[pos], data[pos + 1]]))[0]

        # 拼音索引表
        pos += 2
        py = getWordPy(data[pos: pos + py_table_len])

        # 中文词组
        pos += py_table_len
        for i in range(same):
            # 中文词组长度
            c_len = struct.unpack('H', bytes([data[pos], data[pos + 1]]))[0]
            # 中文词组
            pos += 2
            word = byte2str(data[pos: pos + c_len])
            # 扩展数据长度
            pos += c_len
            ext_len = struct.unpack('H', bytes([data[pos], data[pos + 1]]))[0]
            # 词频
            pos += 2
            count = struct.unpack('H', bytes([data[pos], data[pos + 1]]))[0]

            # 保存
            GTable.append((count, py, word))

            # 到下个词的偏移位置
            pos += ext_len


def scel2txt(file_name):
    print('-' * 60)
    with open(file_name, 'rb') as f:
        data = f.read()

    print("词库名：", byte2str(data[0x130:0x338]))  # .encode('GB18030')
    print("词库类型：", byte2str(data[0x338:0x540]))
    print("描述信息：", byte2str(data[0x540:0xd40]))
    print("词库示例：", byte2str(data[0xd40:startPy]))

    getPyTable(data[startPy:startChinese])
    getChinese(data[startChinese:])


def run(to_file, file=None, dir_path=None):
    """
    sel 多个文件转换
    :param file: sel文件路径 转换单个sel文件
    :param dir_path: sel文件夹路径 若设置 则转换该文件加内所有sel文件
    :param to_file: 转换完成文件路径
    :return:
    """
    if dir_path:
        fin = [fname for fname in os.listdir(in_path) if fname[-5:] == ".scel"]
        for f in fin:
            f = os.path.join(in_path, f)
            scel2txt(f)
    elif file:
        scel2txt(file)
    else:
        raise Exception('参数必须包含file或者dir_path')
    # 保存结果
    with open(to_file, 'w', encoding='utf8') as f:
        f.writelines([word + '
' for count, py, word in GTable])


def dict_merge():
    """
    词典合并
    :return:
    """
    with open('data/medical_dict.txt', encoding='utf8') as f:
        word_set1 = {word.strip() for word in f}
    with open('data/medical_dict2.txt', encoding='utf8') as f:
        word_set2 = {word.strip() for word in f}
    with open('data/medical_dict3.txt', encoding='utf8') as f:
        word_set3 = {word.strip() for word in f}
    word_set = word_set1 | word_set2 | word_set3
    with open('data/words_dict.txt', encoding='utf-8', mode='w') as f:
        for word in word_set:
            f.write(word + '
')


if __name__ == '__main__':
    # run(file='data/细胞词库/医学词汇大全【官方推荐】.scel', to_file='医学词库.txt',)
    run(dir_path="data/细胞词库", to_file="data/cell_dict.txt")　　

经验分享：直接拿来用。

常用函数二：refwork文件转换

    refowrk是一种文献格式，可以用一些科研软件做分析使用，有些场景下我们需要将excel格式的文件转成refwork文件，一下代码可以实现这个功能。

# -*- coding: utf-8 -*-
"""
Datetime: 2020/03/04
author: Zhang Yafei
description: refwork格式转换
数据格式
列  RT,A1,T1,JF,YR,K1,AB,AD
    ...
"""
import pandas as pd


def main(ref_file, to_file):
    """
    :param ref_file: 转换的csv或者excel文件路径
    :param to_file: 转换之后保存的refwork文件路径
    """
    if ref_file.endswith('csv'):
        rawdata = pd.read_csv(ref_file)
    elif ref_file.endswith('xls') or ref_file.endswith('xlsx'):
        rawdata = pd.read_excel(ref_file)
    with open(to_file, 'a') as f:
        for index, item in rawdata.iterrows():
            f.write('RT ' + item.RT)
            A1 = item.A1
            f.write('
' + 'A1 ' + A1)
            T1 = item.T1
            f.write('
' + 'T1 ' + T1)
            YR = item.YR
            f.write('
' + 'YR ' + YR)
            JF = item.JF
            f.write('
' + 'JF ' + JF)
            K1 = item.K1
            f.write('
' + 'K1 ' + K1)
            AB = item.AB
            if pd.notna(AB):
                f.write('
' + 'AB ' + AB)
            AD = item.AD
            if pd.notna(AD):
                f.write('
' + 'AD ' + AD)
            f.write('
DS CNKI')
            if index < rawdata.shape[0] - 1:
                f.write('


')


if __name__ == '__main__':
    main(ref_file='data.xlsx', to_file='result.txt')

经验分享：直接拿来用

常用函数三：xml文档解析

    xml文档经常作为数据传输格式在web领域使用，它有很多优势，但我们平时梳理的数据大多是csv或者exel这种，那么解析xml文档就是一个必备的技能吗，下面以pubmed下载的xml文档解析为例，展示了xml文档解析的整个流程。

# -*- coding: utf-8 -*-

"""
@Datetime: 2019/4/26
@Author: Zhang Yafei
@Description: 07_xml文档解析
"""
import os
import re
import threading
from concurrent.futures import ThreadPoolExecutor

from lxml import etree
import pandas as pd


def pubmed_xpath_parse(path):
    tree = etree.parse(path)
    # 如果xml数据中出现了关于dtd的声明(如下面的例子)，那样的话，必须在使用lxml解析xml的时候，进行相应的声明。
    # parser = etree.XMLParser(load_dtd=True)  # 首先根据dtd得到一个parser(注意dtd文件要放在和xml文件相同的目录)
    # tree = etree.parse('1.xml', parser=parser)  # 用上面得到的parser将xml解析为树结构
    data_list = []
    pmid_set = []
    for articles in tree.xpath('//PubmedArticle'):
        pmid = articles.xpath('MedlineCitation/PMID/text()')[0]
        if pmid in pmid_set:
            continue
        pmid_set.append(pmid)
        Article = articles.xpath('MedlineCitation/Article')[0]
        journal = Article.xpath('Journal/ISOAbbreviation/text()')[0]
        try:
            authors = Article.xpath('AuthorList/Author')
            affiliations_info = set()
            for author in authors:
                # author_name = author.find('LastName').text + ' ' + author.find('ForeName').text
                affiliations = [x.xpath('Affiliation/text()')[0] for x in author.xpath('AffiliationInfo')]
                # author = author_name + ':' + ';'.join(affiliations)
                for affiliation in affiliations:
                    affiliations_info.add(affiliation)
            affiliations_info = ';'.join(affiliations_info)
        except AttributeError:
            affiliations_info = ''
        try:
            date = Article.xpath('Journal/JournalIssue/PubDate/Year/text()')[0]
        except IndexError:
            date = Article.xpath('Journal/JournalIssue/PubDate/MedlineDate/text()')[0]
            date = re.search('d+', date).group(0)
        try:
            mesh_words = []
            for mesh_heading in articles.xpath('MedlineCitation/MeshHeadingList/MeshHeading'):
                if len(mesh_heading.xpath('child::*')) == 1:
                    mesh_words.append((mesh_heading.xpath('child::*'))[0].text)
                    continue
                mesh_name = ''
                for mesh in mesh_heading.xpath('child::*'):
                    if mesh.tag == 'DescriptorName':
                        mesh_name = mesh.xpath('string()')
                        continue
                    if mesh_name and mesh.tag == 'QualifierName':
                        mesh_word = mesh_name + '/' + mesh.xpath('string()')
                        mesh_words.append(mesh_word)
            mesh_words = ';'.join(mesh_words)
        except AttributeError:
            mesh_words = ''
        article_type = '/'.join([x.xpath('./text()')[0] for x in Article.xpath('PublicationTypeList/PublicationType')])
        country = articles.xpath('MedlineCitation/MedlineJournalInfo/Country/text()')[0]
        data_list.append(
            {'PMID': pmid, 'journal': journal, 'affiliations_info': affiliations_info, 'pub_year': date,
             'mesh_words': mesh_words,
             'country': country, 'article_type': article_type, 'file_path': path})
        print(pmid + '	解析完成')
        df = pd.DataFrame(data_list)
        with threading.Lock():
            df.to_csv('pubmed.csv', encoding='utf_8_sig', mode='a', index=False, header=False)


def to_excel(data, path):
    writer = pd.ExcelWriter(path)
    data.to_excel(writer, sheet_name='table', index=False)
    writer.save()


def get_files_path(dir_name):
    xml_files = []
    for base_path, folders, files in os.walk(dir_name):
        xml_files = xml_files + [os.path.join(base_path, file) for file in files if file.endswith('.xml')]
    return xml_files


if __name__ == '__main__':
    files = get_files_path(dir_name='data')
    if not files:
        print('全部解析完成')
    else:
        with ThreadPoolExecutor() as pool:
            pool.map(pubmed_xpath_parse, files)

常用函数四：文本分词

方式一：jieba分词+停用词+自定义词典

# -*- coding: utf-8 -*-

"""
Datetime: 2020/06/25
Author: Zhang Yafei
Description: 文本分词
输入 停用词文件路径 词典文件路径 分词文件路径 表名（可选） 列名 分词结果列名 保存文件名
输出 分词结果-文件
"""
import os
import re

import jieba
import pandas as pd

if not os.path.exists('res'):
    os.mkdir('res')


class TextCut(object):
    def __init__(self, dictionary=None, stopwords=None, ):
        self.dictionary = dictionary
        self.word_list = None
        if self.dictionary:
            jieba.load_userdict(self.dictionary)
        if stopwords:
            with open(stopwords, 'r', encoding='utf-8') as swf:
                self.stopwords = [line.strip() for line in swf]
        else:
            self.stopwords = None

    @staticmethod
    def clean_txt(raw):
        file = re.compile(r"[^0-9a-zA-Zu4e00-u9fa5]+")
        return file.sub(' ', raw)

    def cut(self, text):
        sentence = self.clean_txt(text.strip().replace('
', ''))
        return ' '.join([i for i in jieba.cut(sentence) if i.strip() and i not in self.stopwords and len(i) > 1])

    def cut2(self, text):
        sentence = self.clean_txt(text.strip().replace('
', ''))
        return ' '.join([i for i in jieba.cut(sentence) if
                         i.strip() and i not in self.stopwords and len(i) > 1 and i in self.word_list])

    def run(self, file_path, col_name, new_col_name, to_file, sheet_name=None, word_in_dict=False):
        if sheet_name:
            df = pd.read_excel(file_path, sheet_name=sheet_name)
        else:
            df = pd.read_excel(file_path)
        if word_in_dict:
            with open(self.dictionary, encoding='utf-8') as f:
                self.word_list = [word.strip() for word in f]
            df[new_col_name] = df[col_name].apply(self.cut2)
        else:
            df[new_col_name] = df[col_name].apply(self.cut)
        df.to_excel(to_file, index=False)
        print('######### 处理完成 ############')


if __name__ == "__main__":
    # 1. 分词
    text_cut = TextCut(stopwords='data/stopwords.txt', dictionary='data/word_dict.txt')
    text_cut.run(file_path='data/山西政策.xlsx', sheet_name='1.21-2.20', col_name='全文', new_col_name='全文分词',
                 to_file='res/山西政策_分词.xlsx')　

方式二：jieba分词+信息熵合并

# -*- coding: utf-8 -*-

"""
Datetime: 2020/03/01
Author: Zhang Yafei
Description: 基于信息熵对分词结果进行合并
"""
from collections import Counter
from functools import reduce
from pandas import read_excel, DataFrame


class InfoEntropyMerge(object):
    def __init__(self, data, stopwords='data/stopwords.txt'):
        self.data = data
        self.words_freq_one = {}
        self.words_freq_two = {}
        self.entropy_words_dict = {}
        if stopwords:
            with open(stopwords, 'r', encoding='utf-8') as f:
                self.stopwords = {line.strip() for line in f}
        else:
            self.stopwords = None

    def count_word_freq_one(self, save_to_file=False, word_freq_file=None):
        keywords = (word for word_list in self.data for word in word_list if word)
        self.words_freq_one = Counter(keywords)
        if save_to_file:
            words = [word for word in self.words_freq_one]
            freqs = [self.words_freq_one[word] for word in words]
            words_df = DataFrame(data={'word': words, 'freq': freqs})
            words_df.sort_values('freq', ascending=False, inplace=True)
            words_df.to_excel(word_freq_file, index=False)

    def count_freq(self, word1, word2):
        """
        统计相邻两个词出现的频率
        :param word1:
        :param word2:
        :return:
        """
        if (word1, word2) not in self.words_freq_two:
            self.words_freq_two[(word1, word2)] = 1
        else:
            self.words_freq_two[(word1, word2)] += 1
        return word2

    def count_word_freq_two(self, save_to_file=False, word_freq_file=None):
        """
        计算相邻两个词出现的频率
        :param save_to_file:
        :param word_freq_file:
        :return:
        """
        for word_list in self.data:
            reduce(self.count_freq, word_list)
        if save_to_file and word_freq_file:
            words_list = [(word1, word2) for word1, word2 in self.words_freq_two]
            freqs = [self.words_freq_two[w1_w2] for w1_w2 in words_list]
            words_df = DataFrame(data={'word': words_list, 'freq': freqs})
            words_df.sort_values('freq', ascending=False, inplace=True)
            words_df.to_excel(word_freq_file, index=False)

    @staticmethod
    def is_chinese(word):
        for ch in word:
            if 'u4e00' <= ch <= 'u9fff':
                return True
        return False

    def clac_entropy(self, save_to_file=False, dict_path='data/entropy_dict.txt'):
        """
        计算信息熵: E(w1, w2) = P(w1,w2)/min(P(w1),P(w2))
        :param save_to_file: 是否将熵值大于0.5的新词保存到文件中
        :param dict_path: 保存字典路径
        :return:
        """
        for word1, word2 in self.words_freq_two:
            freq_two = self.words_freq_two[(word1, word2)]
            freq_one_min = min(self.words_freq_one[word1], self.words_freq_one[word2])
            freq_one_max = max(self.words_freq_one[word1], self.words_freq_one[word2])
            w1_w2_entropy = freq_two / freq_one_max
            if self.stopwords:
                if w1_w2_entropy > 0.5 and word1 not in self.stopwords and word2 not in self.stopwords and self.is_chinese(word1) and self.is_chinese(word2):
                    # print(word1, word2, freq_two, freq_one_min, freq_one_max)
                    self.entropy_words_dict[word1+word2] = w1_w2_entropy
            else:
                if w1_w2_entropy > 0.5:
                    self.entropy_words_dict[word1+word2] = w1_w2_entropy

        print('信息熵大于0.5的词语组合:
', self.entropy_words_dict)
        if save_to_file and dict_path:
            with open(dict_path, mode='r+', encoding='utf-8') as f:
                content = f.read()
                f.seek(0, 0)
                for word in self.entropy_words_dict:
                    f.write(word+'
')
                f.write(content)
            print(f'成功将信息熵大于0.5的词语保存到了{dict_path}中')


def data_read(path, col_name):
    df = read_excel(path)
    texts = df.loc[df[col_name].notna(), col_name].str.split()
    return texts


if __name__ == '__main__':
    text_list = data_read(path='res/国家政策_分词.xlsx', col_name='全文分词')
    info_entro = InfoEntropyMerge(data=text_list)
    info_entro.count_word_freq_one()
    info_entro.count_word_freq_two()
    info_entro.clac_entropy(save_to_file=False, dict_path='data/entropy_dict.txt')

经验分享：若有好的词典和停用词，优先选用方式一，否则选择方式二。