generated from LufsX/Challenge-kNN
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@@ -1,7 +1,5 @@
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# function.py
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import numpy as np
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import pandas as pd
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from sklearn.preprocessing import StandardScaler
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"""
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挑战说明:
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@@ -45,22 +43,17 @@ name = "熊浩燃"
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# 这里写自己的代码实现
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def classify0(inX, dataSet, labels, k=3):
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"""
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KNN 分类算法,使用马氏距离。
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KNN 分类算法。
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Args:
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- inX (numpy array): 输入待分类的样本。
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- dataSet (numpy array): 训练数据集。
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- labels (list or numpy array): 训练集对应的标签。
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- k (int): kNN 算法参数,默认值为 3。
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- k (int): kNN 算法参数,请**自行设置默认值**,评测时仅会使用其默认值,不修改默认值将**无法通过**评测,**成绩为零**。
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Returns:
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- int: 预测的分类标签。
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"""
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# 标准化数据
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scaler = StandardScaler()
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dataSet = scaler.fit_transform(dataSet)
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inX = scaler.transform([inX])[0]
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# 计算协方差矩阵的逆
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cov_matrix = np.cov(dataSet, rowvar=False)
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inv_cov_matrix = np.linalg.inv(cov_matrix)
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@@ -81,45 +74,15 @@ def load_data(file_path):
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"""
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加载 TSV 格式数据文件。
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"""
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data = pd.read_csv(file_path, sep='\t', header=None).values
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data = np.loadtxt(file_path, delimiter="\t")
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features = data[:, :-1]
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labels = data[:, -1].astype(int)
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return features, labels
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def find_best_k(X_train, y_train):
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"""
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寻找最佳 k 值。
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"""
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best_k = 1
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best_accuracy = 0
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for k in range(1, 21):
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# 使用 classify0 进行预测
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y_pred = [classify0(x, X_train, y_train, k) for x in X_train]
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accuracy = np.mean(y_pred == y_train)
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if accuracy > best_accuracy:
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best_accuracy = accuracy
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best_k = k
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return best_k, best_accuracy
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if __name__ == "__main__":
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train_file = "datingTestSet2.tsv"
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X, y = load_data(train_file)
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# 以下代码可用于测试,可自行随意修改
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# 标准化特征
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scaler = StandardScaler()
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X = scaler.fit_transform(X)
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# 寻找最佳 k 值
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best_k, best_accuracy = find_best_k(X, y)
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# 输出最佳 k 值和对应的准确率
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print(f"最佳 k 值: {best_k}, 准确率: {best_accuracy:.2f}")
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# 进行预测
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sample = np.array([65915, 3.868359, 0.128078])
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sample = scaler.transform([sample])[0] # 标准化样本
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predicted_label = classify0(sample, X, y, best_k)
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print(f"预测结果: {predicted_label}")
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train_file = "datingTrainSet2.tsv"
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train_data, train_labels = load_data(train_file)
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print(classify0(np.array([65915, 3.868359, 0.128078]), train_data, train_labels))
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