Python机器学习NLP自然语言处理基本操作精确分词

时间：2022-09-08 21:15:23

 

概述

从今天开始我们将开启一段自然语言处理 (NLP) 的旅程. 自然语言处理可以让来处理, 理解, 以及运用人类的语言, 实现机器语言和人类语言之间的沟通桥梁.

Python机器学习NLP自然语言处理基本操作精确分词

 

分词器 jieba

jieba 算法基于前缀词典实现高效的词图扫描, 生成句子中汉字所有可能成词的情况所构成的有向无环图. 通过动态规划查找最大概率路径, 找出基于词频的最大切分组合. 对于未登录词采用了基于汉字成词能力的 HMM 模型, 使用 Viterbi 算法.

Python机器学习NLP自然语言处理基本操作精确分词

 

安装

pip install jieba

Python机器学习NLP自然语言处理基本操作精确分词

查看是否安装成功:

import jieba
print(jieba.__version__)

输出结果:

0.42.1

 

精确分词

精确分词: 精确模式试图将句子最精确地切开, 精确分词也是默认分词.

Python机器学习NLP自然语言处理基本操作精确分词

格式:

jieba.cut(content, cut_all=False)

参数:

  • content: 需要分词的内容
  • cut_all: 如果为 True 则为全模式, False 为精确模式

例子:

import jieba
# 定义文本
content = "自然语言处理是人工智能和语言学领域的分支学科。此领域探讨如何处理及运用自然语言；自然语言处理包括多方面和步骤，基本有认知、理解、生成等部分。"
# 精确分词
seg = jieba.cut(content, cut_all=False)
# 调试输出
print([word for word in seg])

输出结果:

Building prefix dict from the default dictionary ...
Loading model from cache C:UsersWindowsAppDataLocalTempjieba.cache
Loading model cost 0.984 seconds.
Prefix dict has been built successfully.
["自然语言", "处理", "是", "人工智能", "和", "语言学", "领域", "的", "分支", "学科", "。", "此", "领域", "探讨", "如何", "处理", "及", "运用", "自然语言", "；", "自然语言", "处理", "包括", "多方面", "和", "步骤", "，", "基本", "有", "认知", "、", "理解", "、", "生成", "等", "部分", "。"]

 

全模式

全模式分词: 全模式会把句子中所有可能是词语的都扫出来. 速度非常快, 但不能解决歧义问题.

例子:

C:UsersWindowsAnaconda3pythonw.exe "C:/Users/Windows/Desktop/project/NLP 基础/结巴.py"
Building prefix dict from the default dictionary ...
Loading model from cache C:UsersWindowsAppDataLocalTempjieba.cache
["自然", "自然语言", "语言", "处理", "是", "人工", "人工智能", "智能", "和", "语言", "语言学", "领域", "的", "分支", "学科", "。", "此", "领域", "探讨", "如何", "何处", "处理", "及", "运用", "自然", "自然语言", "语言", "；", "自然", "自然语言", "语言", "处理", "包括", "多方", "多方面", "方面", "和", "步骤", "，", "基本", "有", "认知", "、", "理解", "、", "生成", "等", "部分", "。"]
Loading model cost 0.999 seconds.
Prefix dict has been built successfully.

输出结果:

Building prefix dict from the default dictionary ...
Loading model from cache C:UsersWindowsAppDataLocalTempjieba.cache
["自然", "自然语言", "语言", "处理", "是", "人工", "人工智能", "智能", "和", "语言", "语言学", "领域", "的", "分支", "学科", "。", "此", "领域", "探讨", "如何", "何处", "处理", "及", "运用", "自然", "自然语言", "语言", "；", "自然", "自然语言", "语言", "处理", "包括", "多方", "多方面", "方面", "和", "步骤", "，", "基本", "有", "认知", "、", "理解", "、", "生成", "等", "部分", "。"]
Loading model cost 0.999 seconds.
Prefix dict has been built successfully.

 

搜索引擎模式

搜索引擎模式: 在精确模式的基础上, 对长词再次切分. 提高召回率, 适合用于搜索引擎分词.

Python机器学习NLP自然语言处理基本操作精确分词

例子:

import jieba
# 定义文本
content = "自然语言处理是人工智能和语言学领域的分支学科。此领域探讨如何处理及运用自然语言；自然语言处理包括多方面和步骤，基本有认知、理解、生成等部分。"
# 搜索引擎模式
seg = jieba.cut_for_search(content)
# 调试输出
print([word for word in seg])

输出结果:

Building prefix dict from the default dictionary ...
Loading model from cache C:UsersWindowsAppDataLocalTempjieba.cache
[("自然语言", "l"), ("处理", "v"), ("是", "v"), ("人工智能", "n"), ("和", "c"), ("语言学", "n"), ("领域", "n"), ("的", "uj"), ("分支", "n"), ("学科", "n"), ("。", "x"), ("此", "zg"), ("领域", "n"), ("探讨", "v"), ("如何", "r"), ("处理", "v"), ("及", "c"), ("运用", "vn"), ("自然语言", "l"), ("；", "x"), ("自然语言", "l"), ("处理", "v"), ("包括", "v"), ("多方面", "m"), ("和", "c"), ("步骤", "n"), ("，", "x"), ("基本", "n"), ("有", "v"), ("认知", "v"), ("、", "x"), ("理解", "v"), ("、", "x"), ("生成", "v"), ("等", "u"), ("部分", "n"), ("。", "x")]
Loading model cost 1.500 seconds.
Prefix dict has been built successfully.

 

获取词性

通过 jieba.posseg 模式实现词性标注.

import jieba.posseg as psg
# 定义文本
content = "自然语言处理是人工智能和语言学领域的分支学科。此领域探讨如何处理及运用自然语言；自然语言处理包括多方面和步骤，基本有认知、理解、生成等部分。"
# 分词
seg = psg.lcut(content)
# 获取词性
part_of_speech = [(x.word, x.flag) for x in seg]
# 调试输出
print(part_of_speech)

输出结果:

Building prefix dict from the default dictionary ...
Loading model from cache C:UsersWindowsAppDataLocalTempjieba.cache
[("自然语言", "l"), ("处理", "v"), ("是", "v"), ("人工智能", "n"), ("和", "c"), ("语言学", "n"), ("领域", "n"), ("的", "uj"), ("分支", "n"), ("学科", "n"), ("。", "x"), ("此", "zg"), ("领域", "n"), ("探讨", "v"), ("如何", "r"), ("处理", "v"), ("及", "c"), ("运用", "vn"), ("自然语言", "l"), ("；", "x"), ("自然语言", "l"), ("处理", "v"), ("包括", "v"), ("多方面", "m"), ("和", "c"), ("步骤", "n"), ("，", "x"), ("基本", "n"), ("有", "v"), ("认知", "v"), ("、", "x"), ("理解", "v"), ("、", "x"), ("生成", "v"), ("等", "u"), ("部分", "n"), ("。", "x")]
Loading model cost 1.500 seconds.
Prefix dict has been built successfully.

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原文链接：https://blog.csdn.net/weixin_46274168/article/details/120107261

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