python – TypeError:’KFold’对象不可迭代
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A kernel for Credit Card Fraud Detection.
我到达了需要执行KFold的步骤,以便找到Logistic回归的最佳参数. 以下代码显示在内核本身,但由于某种原因(可能是旧版本的scikit-learn,给我一些错误). def printing_Kfold_scores(x_train_data,y_train_data): fold = KFold(len(y_train_data),5,shuffle=False) # Different C parameters c_param_range = [0.01,0.1,1,10,100] results_table = pd.DataFrame(index = range(len(c_param_range),2),columns = ['C_parameter','Mean recall score']) results_table['C_parameter'] = c_param_range # the k-fold will give 2 lists: train_indices = indices[0],test_indices = indices[1] j = 0 for c_param in c_param_range: print('-------------------------------------------') print('C parameter: ',c_param) print('-------------------------------------------') print('') recall_accs = [] for iteration,indices in enumerate(fold,start=1): # Call the logistic regression model with a certain C parameter lr = LogisticRegression(C = c_param,penalty = 'l1') # Use the training data to fit the model. In this case,we use the portion of the fold to train the model # with indices[0]. We then predict on the portion assigned as the 'test cross validation' with indices[1] lr.fit(x_train_data.iloc[indices[0],:],y_train_data.iloc[indices[0],:].values.ravel()) # Predict values using the test indices in the training data y_pred_undersample = lr.predict(x_train_data.iloc[indices[1],:].values) # Calculate the recall score and append it to a list for recall scores representing the current c_parameter recall_acc = recall_score(y_train_data.iloc[indices[1],:].values,y_pred_undersample) recall_accs.append(recall_acc) print('Iteration ',iteration,': recall score = ',recall_acc) # The mean value of those recall scores is the metric we want to save and get hold of. results_table.ix[j,'Mean recall score'] = np.mean(recall_accs) j += 1 print('') print('Mean recall score ',np.mean(recall_accs)) print('') best_c = results_table.loc[results_table['Mean recall score'].idxmax()]['C_parameter'] # Finally,we can check which C parameter is the best amongst the chosen. print('*********************************************************************************') print('Best model to choose from cross validation is with C parameter = ',best_c) print('*********************************************************************************') return best_c 我得到的错误如下:
如果我从这一行中删除shuffle = False,我收到以下错误:
如果我删除5并保持shuffle = False,我收到以下错误;
如果有人可以帮助我解决这个问题,并建议如何使用最新版本的scikit-learn来完成,我们将非常感激. 谢谢. 解决方法
KFold是一个分裂器,所以你必须给分裂.
示例代码: X = np.array([1,1],[2,2,2],[3,3,3],[4,4,4]]) y = np.array([1,4]) # Now you create your Kfolds by the way you just have to pass number of splits and if you want to shuffle. fold = KFold(2,shuffle=False) # For iterate over the folds just use split for train_index,test_index in fold.split(X): X_train,X_test = X[train_index],X[test_index] y_train,y_test = y[train_index],y[test_index] # Follow fitting the classifier 如果你想获得train / test循环的索引,只需添加enumerate for i,train_index,test_index in enumerate(fold.split(X)): print('Iteration:',i) X_train,y[test_index] 我希望这有效 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |