特征重要性分析和筛选

    feature_results = pd.DataFrame({'feature': list(train_features.columns),
                               'importance': model.feature_importances_})
    feature_results = feature_results.sort_values('importance',ascending=False).reset_index(drop=True)
    
    from IPython.core.pylabtools import figsize
    figsize(12, 10)
    plt.style.use('ggplot')
    
    feature_results.loc[:9, :].plot(x = 'feature', y = 'importance', edgecolor = 'k',