generated from LufsX/Experiment-kNN
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-51
@@ -18,6 +18,11 @@ name = "陈宇杰"
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- dataSet (numpy array): 训练数据集或测试数据集,shape 为 (m, 1024)。
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- dataSet (numpy array): 训练数据集或测试数据集,shape 为 (m, 1024)。
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- labels (numpy array): 训练集或测试集对应的标签,shape 为 (m,)。
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- labels (numpy array): 训练集或测试集对应的标签,shape 为 (m,)。
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"""
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"""
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import numpy as np
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import os
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from collections import Counter
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# 加载数据的函数
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def load_dataset(directory):
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def load_dataset(directory):
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file_list = os.listdir(directory)
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file_list = os.listdir(directory)
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data_matrix = []
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data_matrix = []
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@@ -34,14 +39,7 @@ def load_dataset(directory):
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return np.array(data_matrix), np.array(labels)
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return np.array(data_matrix), np.array(labels)
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"""
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# 将32x32的二值图像转换为1x1024的向量
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函数名称: img_to_vector
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功能: 将32x32的二值图像转换为1x1024的向量。
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参数:
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- file_path (str): 图像文件的路径。
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返回值:
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- vector (numpy array): 转换后的1x1024的向量。
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"""
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def img_to_vector(file_path):
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def img_to_vector(file_path):
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vector = np.zeros((1, 1024))
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vector = np.zeros((1, 1024))
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with open(file_path, 'r') as f:
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with open(file_path, 'r') as f:
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@@ -51,61 +49,24 @@ def img_to_vector(file_path):
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vector[0, 32 * i + j] = int(lines[i][j])
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vector[0, 32 * i + j] = int(lines[i][j])
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return vector
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return vector
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"""
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# kNN 分类函数
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函数名称: classify
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功能: 使用kNN算法对输入样本进行分类。
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参数:
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- input_vector (numpy array): 输入待分类的样本,shape 为 (1024,)。
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- dataSet (numpy array): 训练数据集,shape 为 (m, 1024)。
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- labels (list or numpy array): 训练集对应的标签,shape 为 (m,)。
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- k (int): kNN 算法的参数,默认值为3。
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返回值:
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- int: 预测的分类标签。
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"""
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def classify(input_vector, dataSet, labels, k=3):
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def classify(input_vector, dataSet, labels, k=3):
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# 计算欧氏距离
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# 计算欧氏距离
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distances = np.linalg.norm(dataSet - input_vector, axis=1)
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distances = np.linalg.norm(dataSet - input_vector, axis=1)
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# 获取距离最近的k个样本的标签
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# 获取距离最近的k个样本的标签
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nearest_neighbors = np.argsort(distances)[:k]
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nearest_neighbors = np.argsort(distances)[:k]
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nearest_labels = labels[nearest_neighbors]
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nearest_labels = labels[nearest_neighbors]
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# 转换 nearest_labels 为 Python 列表
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# 确保 nearest_labels 是一维的,转换为 Python 列表
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nearest_labels = nearest_labels.tolist()
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nearest_labels = nearest_labels.flatten().tolist()
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# 投票,返回出现次数最多的标签
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# 投票,返回出现次数最多的标签
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most_common = Counter(nearest_labels).most_common(1)
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most_common = Counter(nearest_labels).most_common(1)
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return most_common[0][0]
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return most_common[0][0]
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"""
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# 实验主程序
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函数名称: normalize_data
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功能: 对数据进行归一化处理,将特征缩放到相同范围,通常是 [0, 1]。
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参数:
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- dataSet (numpy array): 需要归一化的训练数据集或测试数据集。
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返回值:
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- normalized_dataSet (numpy array): 归一化后的数据集。
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"""
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def normalize_data(dataSet):
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# 将数据集 reshape 成二维数组
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num_samples = dataSet.shape[0]
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dataSet_reshaped = dataSet.reshape(num_samples, -1)
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# 对数据进行归一化处理
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scaler = MinMaxScaler()
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return scaler.fit_transform(dataSet_reshaped)
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"""
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实验主程序:
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- 加载训练集和测试集。
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- 测试 kNN 算法的分类效果,并计算分类精度。
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"""
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def main():
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def main():
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# 加载训练集和测试集
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# 加载训练集和测试集
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training_data, training_labels = load_dataset('trainingDigits')
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training_data, training_labels = load_dataset('trainingdigits')
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test_data, test_labels = load_dataset('testDigits')
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test_data, test_labels = load_dataset('testdigits')
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# 归一化数据
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training_data = normalize_data(training_data)
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test_data = normalize_data(test_data)
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# 测试 kNN 算法
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# 测试 kNN 算法
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total_tests = len(test_data)
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total_tests = len(test_data)
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