# Extracting features from categorical variables #Extracting features from categorical variables 独热编码 from sklearn.feature_extraction import DictVectorizer onehot_encoder=DictVectorizer() instance=[{'city':'New York'},{'city':'San Francisco'}, {'city
import nltk from nltk.book import * nltk.corpus.gutenberg.fileids() emma = nltk.corpus.gutenberg.words('austen-emma.txt') len(emma) emma = nltk.Text(nltk.corpus.gutenberg.words('austen-emma.txt')) emma.concordance("surprize") from nltk.corpus im
假设有一段文本:"I have a cat, his name is Huzihu. Huzihu is really cute and friendly. We are good friends." 那么怎么提取这段文本的特征呢? 一个简单的方法就是使用词袋模型(bag of words model).选定文本内一定的词放入词袋,统计词袋内所有词在文本中出现的次数(忽略语法和单词出现的顺序),将其用向量的形式表示出来. 词频统计可以用scikit-learn的CountVectori
# 文字特征提取 词库模型(bag of words) 2016年2月26,星期五 # 1.词库表示法 In [9]: # sklearn 的 CountVectorizer类能够把文档词块化(tokenize),代码如下 from sklearn.feature_extraction.text import CountVectorizer corpus=['UNC played Duke in basketball','Duke lost the basketball game','I ate