python机器学习及实践（从零开始kaggle竞赛之路）第二章的2.1.2.5集成模型程序报错：numpy.core._internal.AxisError: axis 0 is out of bo

python机器学习及实践（从零开始kaggle竞赛之路）第二章的2.1.2.5集成模型程序报错：numpy.core._internal.AxisError: axis 0 is out of bounds for array of dimension 0:
1.原因是本段代码在python3以上执行时：
print(np.sort(zip(etr.feature_importances_,bosten.feature_names),axis=0))zip函数返回的是迭代器结果
在python2.7下执行是通过的
2.修改代码为：
print(np.sort(list(zip(etr.feature_importances_,bosten.feature_names)),axis=0))结果通过：
[['0.00393385852727' 'AGE']
 ['0.00823453398696' 'B']
 ['0.0137169582645' 'CHAS']
 ['0.0170472963716' 'CRIM']
 ['0.0195123294833' 'DIS']
 ['0.0196218058374' 'INDUS']
 ['0.026176925494' 'LSTAT']
 ['0.0285497800029' 'NOX']
 ['0.0294926254675' 'PTRATIO']
 ['0.059896715878' 'RAD']
 ['0.0625512807314' 'RM']
 ['0.334454711687' 'TAX']
 ['0.376811178269' 'ZN']]