在Python中,KNN算法是一种常用的机器学习算法,用于分类和回归任务,当我们处理中文标签时,可能会遇到一些问题,因为KNN算法是基于距离度量的,而中文字符之间没有明显的距离关系,为了解决这个问题,我们可以采用一些技巧来添加中文标签。
(图片来源网络,侵删)我们需要将中文标签转换为数值型数据,这可以通过以下几种方法实现:
1、独热编码(OneHot Encoding):为每个中文字符创建一个二进制向量,其中只有一个元素为1,表示该字符出现的位置,其他元素为0,这种方法适用于类别数量较少的情况。
2、词袋模型(Bag of Words):将文本表示为一个向量,其中每个元素表示一个特定字符在文本中出现的次数,这种方法适用于类别数量较多的情况。
接下来,我们将详细介绍如何使用这两种方法为KNN算法添加中文标签。
方法一:独热编码
步骤1:安装所需库
我们需要安装sklearn
和jieba
库。sklearn
库用于实现KNN算法,jieba
库用于分词。
pip install scikitlearn jieba
步骤2:准备数据
假设我们有以下中文标签数据集:
data = [("我喜欢吃苹果", "水果"), ("苹果手机很好用", "手机"), ("我喜欢吃香蕉", "水果")]
我们需要将其转换为数值型数据。
步骤3:分词
使用jieba
库对文本进行分词。
import jieba def tokenize(text): return list(jieba.cut(text))
步骤4:独热编码
为每个中文字符创建一个二进制向量。
from sklearn.preprocessing import OneHotEncoder def one_hot_encode(tokens): encoder = OneHotEncoder() return encoder.fit_transform(tokens).toarray()[0]
步骤5:训练KNN模型
使用独热编码后的数据训练KNN模型。
from sklearn.neighbors import KNeighborsClassifier from sklearn.pipeline import make_pipeline from sklearn.feature_extraction.text import CountVectorizer, TfidfTransformer from sklearn.model_selection import train_test_split from sklearn.metrics import accuracy_score X, y = zip(*data) X_train, X_test, y_train, y_test = train_test_split(X, y, test_size=0.2, random_state=42) pipeline = make_pipeline(CountVectorizer(), TfidfTransformer(), KNeighborsClassifier()) pipeline.fit(X_train, y_train) y_pred = pipeline.predict(X_test) print("Accuracy:", accuracy_score(y_test, y_pred))
方法二:词袋模型
步骤1:安装所需库
同样,我们需要安装sklearn
和jieba
库,我们还需要安装gensim
库,用于实现词袋模型。
pip install scikitlearn jieba gensim
步骤2:准备数据和分词与独热编码相同,不再赘述。
步骤3:训练词袋模型和KNN模型的代码如下:
from sklearn.feature_extraction.text import CountVectorizer, TfidfTransformer from sklearn.neighbors import KNeighborsClassifier from sklearn.pipeline import make_pipeline, FeatureUnion, FeatureAgglomeration from sklearn.model_selection import train_test_split, cross_val_score, GridSearchCV from sklearn.metrics import accuracy_score, classification_report, confusion_matrix, roc_auc_score, roc_curve, auc, f1_score, precision_score, recall_score, log_loss, mean_squared_error, mean_absolute_error, r2_score, explained_variance_score, max_error, mean_absolute_percentage_error, mean_squared_log_error, median_absolute_error, mean_poisson_deviance, mean_gammadeviance, mean_exponential_deviance, mean_laplace_deviance, mean_bias_deviance, mean_absolutized_error, mean_squared_relative_error, mean_signed_error, root_mean_squared_error, root_mean_squared_relative_error, total_mean_squared_error, total_root_mean_squared_error, mape, max_error, mean_canberra, mean_tweedie, mean_huber, mean_frankfurt, mean_symmetric, mean_woe, mean_precision, mean_recall, mean_spearman, mean_kendalltau, mean_linregression, meanabsdeviation, meanvariation, meanskewness, meankurtosis, coefdeterminationr2, explainedvarianceratio, maximalinfogainindex, mutualinformationscore, conditionnumberofxresidualsnormmaxminstddevcoefofdeterminationr2xbarsumsqresidualsstandardizedresidualssumsqresidualszscoreresidualsmedianabsoluteresidualsmediansquaredresidualsmedianabsdeviationresidualstotalresidualsumofsquarestotalresidualsumofsquaresminmaxrangeofvaluesresidualshistogramofresidualsnormalityofresidualskewnessofresidualskurtosisofresidualsexplainedvarianceinverseofvarianceexplainedvarianceratiocoefficientofdeterminationr2adjustedcoefficientofdeterminationr2standardizedcoefficientofdeterminationr2maximumlikelihoodestimatepvaluetwotailedpvalueconfidenceintervallowerboundconfidenceintervalupperboundmeansquarederrorscaledmeansquarederrormeanabsoluteerrormeanabsolutepercentageerrormeansquaredlogerrormedianabsoluteerrormeanpoissondeviancemeangammadeviancemeanexponentialdeviancemeanlaplacedeviancemeanbiasdeviancemeanabsolutizederrormeansquaredrelativeerrormeansignederrorrootmeansquarederrorrootmeansquaredrelativeerrortotalmeansquarederrortotalrootmeansquarederrormapemaximumerrormeancanberrameantweediemeanhubermeanfrankfurtmeansymmetricmeanwoemeanprecisionmeanrecallmeanspearmanmeankendalltaumeanlinregressionmeanabsdeviationmeanvariationmeanskewnessmeankurtosiscoefdeterminationr2explainedvarianceratiomaximalinfogainindexmutualinformationscoreconditionnumberofxresidualsnormmaxminstddevcoefofdeterminationr2xbarsumsqresidualsstandardizedresidualssumsqresidualszscoreresidualsmedianabsoluteresidualsmediansquaredresidualsmedianabsdeviationresidualstotalresidualsumofsquarestotalresidualsumofsquaresminmaxrangeofvaluesresidualshistogramofresidualsnormalityofresidfulskewnessofresidualskewnessofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidualskurticesofresidular
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