generated from LufsX/Challenge-kNN
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@@ -38,7 +38,7 @@ name = "吴俊煯"
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# 这里写自己的代码实现
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# 这里写自己的代码实现
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def classify0(inX, dataSet, labels,k=4):
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def classify0(inX, dataSet, labels,k=3):
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"""
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"""
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KNN 分类算法。
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KNN 分类算法。
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@@ -50,27 +50,23 @@ def classify0(inX, dataSet, labels,k=4):
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Returns:
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Returns:
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- int: 预测的分类标签。
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- int: 预测的分类标签。
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"""
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"""
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if dataSet.shape[0] == 0:
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# 特征缩放
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raise ValueError("数据集为空")
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scaler = StandardScaler()
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dataSet_scaled = scaler.fit_transform(dataSet)
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inX_scaled = scaler.transform(inX.reshape(1, -1))
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# 确保 k 不大于数据集的大小
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# KNN 分类
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k = min(k, dataSet.shape[0])
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dataSetSize = dataSet_scaled.shape[0]
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diffMat = np.tile(inX_scaled, (dataSetSize, 1)) - dataSet_scaled
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# 计算测试样本与每个训练样本之间的距离
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diffMat = np.tile(inX, (dataSet.shape[0], 1)) - dataSet
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sqDiffMat = diffMat ** 2
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sqDiffMat = diffMat ** 2
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distances = np.sqrt(sqDiffMat.sum(axis=1))
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distances = np.sqrt(sqDiffMat.sum(axis=1))
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# 对距离进行排序,并获取索引
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sortedDistIndicies = distances.argsort()
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sortedDistIndicies = distances.argsort()
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# 选择距离最小的k个点
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classCount = {}
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classCount = {}
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for i in range(k):
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for i in range(k):
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voteIlabel = labels[sortedDistIndicies[i]]
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voteIlabel = labels[sortedDistIndicies[i]]
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classCount[voteIlabel] = classCount.get(voteIlabel, 0) + 1
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classCount[voteIlabel] = classCount.get(voteIlabel, 0) + 1
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# 多数投票
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sortedClassCount = sorted(classCount.items(), key=lambda item: item[1], reverse=True)
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sortedClassCount = sorted(classCount.items(), key=lambda item: item[1], reverse=True)
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return sortedClassCount[0][0]
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return sortedClassCount[0][0]
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