import pandas as pd from sklearn.model_selection import GroupShuffleSplit df = pd.read_csv('horse_race_data.csv') gss = GroupShuffleSplit(test_size=.40, n_splits=1, \ random_state=7).split(df, groups=df['id']) # 生成训练集和验证集的索引 X_train_inds, X_test_inds = next(gss) train_data= df.iloc[X_train_inds] X_train = train_data.loc[:, ~train_data.columns.isin(['id','rank'])] y_train = train_data.loc[:, train_data.columns.isin(['rank'])] test_data= df.iloc[X_test_inds] X_test = test_data.loc[:, ~test_data.columns.isin(['rank'])] y_test = test_data.loc[:, test_data.columns.isin(['rank'])]

这段代码是使用pandas和sklearn库来处理horse_race_data.csv文件中的数据，并将其划分为训练集和验证集。首先，使用pandas读取csv文件并存储为DataFrame对象df。然后，使用GroupShuffleSplit函数将数据集按照指定的组进行划分，其中test_size参数设置为0.40，表示将40%的数据划分为验证集，n_splits参数设置为1，表示只进行一次划分，random_state参数设置为7，用于生成随机数种子以确保可重复性。接下来，通过调用next函数获取生成的划分索引，将索引分别应用于训练集和验证集，并将特征和标签分开存储。最后，将训练集和验证集的特征和标签分别存储在X_train、y_train、X_test和y_test变量中。

相关问题

import numpy as np import pandas import pandas as pd import matplotlib from sklearn import naive_bayes from sklearn.preprocessing import MinMaxScaler from sklearn.preprocessing import StandardScaler from sklearn.preprocessing import normalize from sklearn.preprocessing import Binarizer from sklearn.impute import SimpleImputer from sklearn.preprocessing import OneHotEncoder import matplotlib.pyplot as plt from sklearn.metrics import roc_curve, auc from sklearn.model_selection import train_test_split from sklearn.linear_model import LogisticRegression from sklearn.metrics import confusion_matrix matplotlib.rc("font", family='Microsoft YaHei') data=pd.read_csv(r'D:\杂货铺\机器学习\银行数据集.csv',header=None)

这段代码导入了一系列的Python库，包括NumPy、Pandas、Matplotlib、scikit-learn等。其中，NumPy是Python科学计算的核心库，Pandas是数据处理的重要库，Matplotlib是绘图库，scikit-learn是机器学习库。接下来，使用Pandas读取一个CSV文件，该文件路径为D:\杂货铺\机器学习\银行数据集.csv，文件没有列名，所以header参数设置为None。

修改代码，使用其他方式跳过错误行，import pandas as pd from sklearn.feature_extraction.text import TfidfVectorizer from sklearn.model_selection import train_test_split from sklearn.naive_bayes import MultinomialNB #加载 CSV 文件并忽略错误行 train_df = pd.read_csv('train.csv', encoding='utf-8', error_bad_lines=False) test_df = pd.read_csv('test.csv', encoding='utf-8', error_bad_lines=False) #删除无效行 train_df.dropna(inplace=True) test_df.dropna(inplace=True) #划分训练集和测试集 X_train = train_df['content'] y_train = train_df['category'] X_test = test_df['content'] y_test = test_df #特征提取 vectorizer = TfidfVectorizer() X_train = vectorizer.fit_transform(X_train) X_test = vectorizer.transform(X_test) #训练模型 model = MultinomialNB() model.fit(X_train, y_train) #测试模型 score = model.score(X_test, y_test) print('Accuracy:', score)

import pandas as pd
from sklearn.feature_extraction.text import TfidfVectorizer
from sklearn.model_selection import train_test_split
from sklearn.naive_bayes import MultinomialNB

#加载 CSV 文件并忽略错误行
try:
train_df = pd.read_csv('train.csv', encoding='utf-8')
except:
pass

try:
test_df = pd.read_csv('test.csv', encoding='utf-8')
except:
pass

#删除无效行
train_df.dropna(inplace=True)
test_df.dropna(inplace=True)

#划分训练集和测试集
X_train = train_df['content']
y_train = train_df['category']
X_test = test_df['content']
y_test = test_df

#特征提取
vectorizer = TfidfVectorizer()
X_train = vectorizer.fit_transform(X_train)
X_test = vectorizer.transform(X_test)

#训练模型
model = MultinomialNB()
model.fit(X_train, y_train)

#测试模型
score = model.score(X_test, y_test)
print('Accuracy:', score)