更新 function.py

function.py

@@ -55,17 +55,25 @@ def classify0(inX, dataSet, labels, k=1):
     Returns:
     - int: 预测的分类标签。
     """
-    dataSetSize=dataSet.shape[0]
-    diffMat=inX - dataSet
-    sqDiffMat=diffMat**2
-    sqDistances=sqDiffMat.sum(axis=1)
-    distances=sqDistances**0.5
-    sortedDistIndicies=distances.argsort()
-    classCount={}
+    dataSetSize = dataSet.shape[0]
+    
+    # 计算协方差矩阵及其逆矩阵
+    cov_matrix = np.cov(dataSet, rowvar=False)
+    inv_cov_matrix = np.linalg.inv(cov_matrix)
+    
+    # 计算马氏距离
+    diffMat = inX - dataSet
+    left_term = np.dot(diffMat, inv_cov_matrix)
+    mahalanobis_distances = np.sqrt(np.sum(left_term * diffMat, axis=1))
+
+    # 排序距离并选择前 k 个最近邻
+    sortedDistIndicies = mahalanobis_distances.argsort()
+    classCount = {}
     for i in range(k):
-        votellabel=labels[sortedDistIndicies[i]]
-        classCount[votellabel]=classCount.get(votellabel,0)+1
-    sortedClassCount=sorted(classCount.items(),key=operator.itemgetter(1),reverse=True)
+        vote_label = labels[sortedDistIndicies[i]]
+        classCount[vote_label] = classCount.get(vote_label, 0) + 1
+
+    sortedClassCount = sorted(classCount.items(), key=operator.itemgetter(1), reverse=True)
     return sortedClassCount[0][0]