解决了errer:Unknown label type: 'unknown'

错误代码：

model = ExtraTreesClassifier()
model.fit(x,y)
for i in range(x.shape[1]):
    print(data_raw.columns[i],format(model.feature_importances_[i],'.3f'))

　　errer：

ValueError: Unknown label type: 'unknown'

　　修改--解决

model = ExtraTreesClassifier()
model.fit(x,y.astype('int'))
for i in range(x.shape[1]):
    print(data_raw.columns[i],format(model.feature_importances_[i],'.3f'))

　　解决问题