diff --git a/function.py b/function.py index f3f6268..4be52bc 100644 --- a/function.py +++ b/function.py @@ -40,27 +40,83 @@ name = "章程鸿" # 这里写自己的代码实现 +import numpy as np +from collections import Counter -def normalize_data(data): - """ - 对数据进行Min-Max归一化。 - - Args: - - data (numpy array): 原始数据。 - - Returns: - - numpy array: 归一化后的数据。 - """ - min_vals = np.min(data, axis=0) - max_vals = np.max(data, axis=0) - ranges = max_vals - min_vals - norm_data = np.where(ranges == 0, 0, (data - min_vals) / ranges) - return norm_data - -# 在加载数据后调用归一化函数 -train_data_normalized = normalize_data(train_data) -test_point_normalized = normalize_data(test_point.reshape(1, -1))[0] # 注意test_point需要reshape为二维数组 - -# 使用归一化后的数据进行分类 -predicted_label_normalized = classify0(test_point_normalized, train_data_normalized, train_labels) -print("归一化后预测的分类标签是:", predicted_label_normalized) \ No newline at end of file +def classify0(inX, dataSet, labels, k=1): + """ + KNN 分类算法。 + + Args: + - inX (numpy array): 输入待分类的样本。 + - dataSet (numpy array): 训练数据集。 + - labels (list or numpy array): 训练集对应的标签。 + - k (int): KNN 算法参数,默认为3。 + + Returns: + - int: 预测的分类标签。 + """ + # 计算距离 + diffMat = inX - dataSet + sqDiffMat = diffMat ** 2 + sqDistances = sqDiffMat.sum(axis=1) + distances = sqDistances ** 0.5 + + # 排序并选取前k个最小距离 + sortedDistIndices = distances.argsort() + classCount = {} + + for i in range(k): + voteIlabel = labels[sortedDistIndices[i]] + classCount[voteIlabel] = classCount.get(voteIlabel, 0) + 1 + + # 返回出现频率最高的类别 + sortedClassCount = sorted(classCount.items(), key=lambda x: x[1], reverse=True) + return sortedClassCount[0][0] + +def load_data(file_path): + """ + 加载 TSV 格式数据文件。 + """ + data = np.loadtxt(file_path, delimiter="\t") + features = data[:, :-1] + labels = data[:, -1].astype(int) + return features, labels + +def normalize_min_max(data): + """ + 对数据进行最小-最大缩放归一化。 + + Args: + - data (numpy array): 待归一化的数据。 + + Returns: + - numpy array: 归一化后的数据。 + """ + min_vals = data.min(0) + max_vals = data.max(0) + ranges = max_vals - min_vals + # 避免除以零的情况 + ranges[ranges == 0.0] = 1.0 + m = data.shape[0] + norm_data = data - np.tile(min_vals, (m, 1)) + norm_data = norm_data / np.tile(ranges, (m, 1)) + return norm_data, min_vals, max_vals + +if __name__ == "__main__": + # 以下代码可用于测试,可自行随意修改 + train_file = "datingTrainSet2.tsv" + + # 加载训练数据 + train_data, train_labels = load_data(train_file) + + # 归一化训练数据,并获取最小值和最大值 + train_data_normalized, min_vals, max_vals = normalize_min_max(train_data) + + # 测试数据点也需要用同样的方式归一化 + test_point = np.array([65915, 3.868359, 0.128078]) + test_point_normalized = (test_point - min_vals) / (max_vals - min_vals) + + # 使用归一化后的数据进行预测 + predicted_label = classify0(test_point_normalized, train_data_normalized, train_labels) + print("预测的分类标签是:", predicted_label) \ No newline at end of file