Update utils.py

Author: luwill

charpter12_XGBoost/utils.py

@@ -13,6 +13,7 @@ def feature_split(X, feature_i, threshold):
 
     return np.array([X_left, X_right])
 
+
 ### 计算基尼指数
 def calculate_gini(y):
     y = y.tolist()
@@ -34,4 +35,4 @@ def cat_label_convert(y, n_col=None):
         n_col = np.amax(y) + 1
     one_hot = np.zeros((y.shape[0], n_col))
     one_hot[np.arange(y.shape[0]), y] = 1
-    return one_hot
+    return one_hot