AttributeError：“str”对象在拟合逻辑回归模型中没有属性“decode”

Question

我目前正在尝试使用逻辑回归创建二元分类。目前我正在确定特征的重要性。我已经进行了数据预处理（一次热编码和采样）并使用 XGBoost 和 RandomFOrestClassifier 运行它，没问题

但是，当我尝试拟合 LogisticRegression 模型时（以下是我在 Notebook 中的代码），

from sklearn.linear_model import LogisticRegression

#Logistic Regression
# fit the model
model = LogisticRegression()
# fit the model
model.fit(np.array(X_over), np.array(y_over))
# get importance
importance = model.coef_[0]
# summarize feature importance
df_imp = pd.DataFrame({'feature':list(X_over.columns), 'importance':importance})
display(df_imp.sort_values('importance', ascending=False).head(20))

# plot feature importance
plt.bar(list(X_over.columns), importance)
plt.show()

报错

...
~\AppData\Local\Continuum\anaconda3\lib\site-packages\joblib\parallel.py in <listcomp>(.0)
    223         with parallel_backend(self._backend, n_jobs=self._n_jobs):
    224             return [func(*args, **kwargs)
--> 225                     for func, args, kwargs in self.items]
    226 
    227     def __len__(self):

~\AppData\Local\Continuum\anaconda3\lib\site-packages\sklearn\linear_model\_logistic.py in _logistic_regression_path(X, y, pos_class, Cs, fit_intercept, max_iter, tol, verbose, solver, coef, class_weight, dual, penalty, intercept_scaling, multi_class, random_state, check_input, max_squared_sum, sample_weight, l1_ratio)
    762             n_iter_i = _check_optimize_result(
    763                 solver, opt_res, max_iter,
--> 764                 extra_warning_msg=_LOGISTIC_SOLVER_CONVERGENCE_MSG)
    765             w0, loss = opt_res.x, opt_res.fun
    766         elif solver == 'newton-cg':

~\AppData\Local\Continuum\anaconda3\lib\site-packages\sklearn\utils\optimize.py in _check_optimize_result(solver, result, max_iter, extra_warning_msg)
    241                 "    https://scikit-learn.org/stable/modules/"
    242                 "preprocessing.html"
--> 243             ).format(solver, result.status, result.message.decode("latin1"))
    244             if extra_warning_msg is not None:
    245                 warning_msg += "\n" + extra_warning_msg

AttributeError: 'str' object has no attribute 'decode'    

我用谷歌搜索了它，大多数回复都说这个错误是因为 scikit-learn 库试图解码一个已经解码的字符串。但我不知道如何在我的情况下解决它。我确保我的所有数据都是整数或 float64，并且没有字符串。

Answer 1

solver='lbfgs' 存在错误。 更改为“sag”可以解决它。

Answer 2

我尝试使用以下命令升级我的scikit-learn，但仍然没有解决AttributeError: 'str' object has no attribute 'decode' 问题

pip install scikit-learn  -U

最后，下面的代码 sn -p 解决了这个问题，将求解器添加为liblinear

model = LogisticRegression(solver='liblinear')

Answer 3

在最新版本的 scikit-learn（现为 0.24.1）中，问题已得到修复，将部分代码包含在我在下面报告的 try-catch 块中：文件是

optimize.py -> _check_optimize_result(solver, result, max_iter=None,
                       extra_warning_msg=None)

代码片段是

if solver == "lbfgs":
    if result.status != 0:
        try:
            # The message is already decoded in scipy>=1.6.0
            result_message = result.message.decode("latin1")
        except AttributeError:
            result_message = result.message
            warning_msg = (
                "{} failed to converge (status={}):\n{}.\n\n"
                "Increase the number of iterations (max_iter) "
                "or scale the data as shown in:\n"
                "    https://scikit-learn.org/stable/modules/"
                "preprocessing.html"
            ).format(solver, result.status, result_message)

刚刚

if solver == "lbfgs":
    if result.status != 0:
        warning_msg = (
            "{} failed to converge (status={}):\n{}.\n\n"
            "Increase the number of iterations (max_iter) "
            "or scale the data as shown in:\n"
            "    https://scikit-learn.org/stable/modules/"
            "preprocessing.html"
        ).format(solver, result.status, result.message.decode("latin1"))

之前。 所以升级 scikit-learn 解决了这个问题。