andrew ng machine learning python

=linearr.predict (X_train) #基于训练集得到的线性y值Plt.figure ()Plt.scatter (x_train,y_train,color= ' green ') #原始训练集数据散点图Plt.plot (x_train,y_train_pred,color= ' black ', linewidth=4) #线性回归的拟合线Plt.title (' Train ') #标题Plt.show ()Y_test_pred=linearr.predict (X_test)Plt.scatter (x_test,y_test,color= ' green ') #绘制测试集数据散点图Plt.plot (x_test,y_test_pred,color= ' black ', linewidth=4) #基于线性回归的预测线Plt.title (' Test ')Plt.show ()Print (' mse= ', Sm.mean_squared_error (y_test,y_test_pred)) #MSE值Print (' r2= ', Sm.r2_

Installation sudo yum install NumPy From numpy Import * Produces an array Random.rand (4,5) Result Array ([[0.79056842, 0.31659893, 0.34054779, 0.97328131, 0.32648329], [0.51585845, 0.70683055, 0.31476985, 0.07952725, 0.80907845], [0.81623517, 0.61038487, 0.66679161, 0.77412742, 0.03394483], [0.41758993, 0.54425978, 0.65350633, 0.90397197, 0.72706079]]) Produce a matrix >>> Randmat=mat (Random.rand (bis)) >>> randmat.i Matrix ([[[1.72265179, 0.82071484, 0.8218207,-3.20005387], [0.60602642,-1.28

Misc.forsale 0.91 0.70 0.79 257 the Rec.autos 0.89 0.89 0.89 238 - Rec.motorcycles 0.98 0.92 0.95 276 - Rec.sport.baseball 0.98 0.91 0.95 251 the Rec.sport.hockey 0.93 0.99 0.96 233 the Sci.crypt 0.86 0.98 0.91 238 the sci.electronics 0.85 0.88 0.86 249 the sci.med 0.92 0.94 0.93 245 - sci.space 0.89 0.96 0.92 221 the Soc.religion.christian 0.78 0.96 0.86 232 the talk.politics.guns 0.88 0.96 0.92 251 the talk.politics.mideast 0.90 0.98 0.94 23194 Talk.politics.misc 0.79 0.89 0.84 188 the Talk.r

:", X) - Print("Y:", Y) - innumiterations=100000 -alpha=0.0005 toTheta=np.ones (x.shape[1]) +Theta=graientdescent (x,y,theta,alpha,x.shape[0],numiterations) - Print(Theta)Operation Result:...... Too many output data to intercept only the next more than 10 linesIteration 99988/cost:3.930135Iteration 99989/cost:3.930135Iteration 99990/cost:3.930135Iteration 99991/cost:3.930135Iteration 99992/cost:3.930135Iteration 99993/cost:3.930135Iteration 99994/cost:3.930135Iteration 99995/cost:3.930135Iterat

* (XMAT.T * (Weights *Ymat)) returnTestPoint *SigmadefLwlrtest (Testarr,xarr,yarr,k = 1.0): M=shape (Testarr) [0] Yhat=zeros (m) forIinchRange (m): Yhat[i]=LWLR (testarr[i],xarr,yarr,k)returnYhatThe LWLR () function is the code for locally weighted linear regression, and the function of the lwlrtest () function is to make the LWLR () function traverse the entire data set. We also need to draw a picture to see how the results fit. def PlotLine1 (testarr,xarr,yarr,k = 1.0 = Mat (Xarr) ymat = Ma

[:, 1].max () + 1 xx1, xx2 = Np.meshgrid (Np.arange (X1_min, X1_max, resolution), Np.aran GE (X2_min, X2_max, resolution)) Z = Classifier.predict (Np.array ([Xx1.ravel (), Xx2.ravel ()]). T) Z = Z.reshape (xx1.shape) Plt.contourf (xx1, xx2, Z, alpha=0.4, Cmap=cmap) Plt.xlim (Xx1.min (), Xx1.max ()) Plt.ylim (Xx2.min (), Xx2.max ()) # Plot all samples for IDX, C1 in enumerate (Np.unique (y)): Print Idx,c1 Plt.scatter (X=x[y = = C1, 0], Y=x[y = = C1, 1], alpha=0.8, C=cmap (IDX), MARKER=M

', Standardscaler ()), ('CLF', Logisticregression (penalty='L2', random_state=0)]) train_sizes, train_scores, Test_scores= Learning_curve (ESTIMATOR=PIPE_LR, X=x_train, Y=y_train, Train_sizes=np.linspace (0.1, 1.0, ten), cv=10, N_jobs=1) Train_mean= Np.mean (Train_scores, Axis=1) TRAIN_STD= NP.STD (Train_scores, Axis=1) Test_mean= Np.mean (Test_scores, Axis=1) TEST_STD= NP.STD (Test_scores, Axis=1) Plt.plot (train_sizes, Train_mean, color='Blue', marker='0', Markersize=5, label='Training Accurac

understand computer knowledge, psychology and philosophy. Artificial intelligence consists of a very wide range of sciences, consisting of a variety of fields, such as machine learning, computer vision, and so on, in general, one of the main goals of AI research is to make machines capable of doing complex work that normally requires human intelligence. But different times, different people's understanding

See Original book section 1.5General process for building predictive modelsThe problem of the daily language expression--the problem of the mathematical language restatementRestatement of problems, extraction features, training algorithms, evaluation algorithmsFamiliar with the input data structure of the different algorithms:1. Features required to extract or combine predictions2. Set the training target3. Training model4. Evaluate the performance of the model on training dataMachine learning:D

This article mainly introduces the knowledge of Perceptron, uses the theory + code practice Way, and carries out the learning of perceptual device. This paper first introduces the Perceptron model, then introduces the Perceptron learning rules (Perceptron learning algorithm), finally through the Python code to achieve

The task of supervised learning in machine learning focuses on predicting the target/marker of an unknown sample based on existing empirical knowledge.According to the different types of target predictor variables, we divide the task of supervised learning into two categories: Classification

Full Stack Engineer Development Manual (author: Shangpeng) Python Tutorial Full Solution Keras uses a depth network to achieve the encoding, that is, the n-dimensional characteristics of each sample, using K as a feature to achieve the function of coding compression. The feature selection function is also realized. For example, the handwriting contains 754 pixels, and it contains 754 features, if you want to represent them with two features. How do yo

(Ss_y.inverse_transform (y_test), Ss_y.inverse_transform (lr_y_predict)) $ Print("the mean square error of the linear is:", Lr_mse) -Lr_mae =Mean_absolute_error (Ss_y.inverse_transform (y_test), Ss_y.inverse_transform (lr_y_predict)) - Print("the average absolute error of the linear is:", Lr_mae) - A #evaluation of the SGD model +Sgdr_score =Sgdr.score (x_test, y_test) the Print("the default evaluation value for SGD is:", Sgdr_score) -sgdr_r_squared =R2_score (y_test, sgdr_y_predict) $ Print("

regression tree is:", Dtr.score (X_test, y_test)) - Print("the r_squared values for the flat regression tree are:", R2_score (Y_test, dtr_y_predict)) - Print("the mean square error of the regression tree is:", Mean_squared_error (Ss_y.inverse_transform (y_test), - Ss_y.inverse_transform (dtr_y_predict))) A Print("the average absolute error of the regression tree is:", Mean_absolute_error (Ss_y.inverse_transform (y_test), + Ss_y.inverse_transform (dtr_y_predict))) the - " " $ the default evalua

.score (X_train_poly2, Y_train))#0.9816421639597427Two-time linear regression model fitted curves:The fitting degree is better than 1 linear fitting.The following 4 linear regression models are performed:1 #four-time linear regression model fitting2Poly4 = Polynomialfeatures (degree=4)#4-time polynomial feature generator3X_train_poly4 =poly4.fit_transform (X_train)4 #Building Model Predictions5Regressor_poly4 =linearregression ()6 Regressor_poly4.fit (X_train_poly4, Y_train)7 #draw a graph of 2

training sample Ax = titanic[["Pclass"," Age","Sex"]] aty = titanic["survived"] - #The average complement of the acquired age space -x[" Age"].fillna (x[" Age"].mean (), inplace=True) - - #split training data and test data -X_train, X_test, y_train, y_test =train_test_split (x, in y, -test_size=0.25, toRandom_state=33) + #extracting dictionary features for vectorization -VEC =Dictvectorizer () theX_train = Vec.fit_transform (X_train.to_dict (orient="Record")) *X_test = Vec.transform (X_test.to

= Polynomialfeatures (degree=4)#4-time polynomial feature generator -X_train_poly4 =poly4.fit_transform (X_train) Wu #Building Model Predictions -Regressor_poly4 =linearregression () About Regressor_poly4.fit (X_train_poly4, Y_train) $X_test_poly4 =poly4.transform (x_test) - Print("four-time linear model prediction score:", Regressor_poly4.score (X_test_poly4, Y_test))#0.8095880795746723 - - #learning and predicting using L1 norm regularization line

AboutDTC =Decisiontreeclassifier () $ #Training - Dtc.fit (X_train, Y_train) - #Predicting saved results -Y_predict =dtc.predict (x_test) A + " " the 4 Model Evaluation - " " $ Print("accuracy:", Dtc.score (X_test, y_test)) the Print("Other indicators: \ n", Classification_report (Y_predict, Y_test, target_names=['died','survived'])) the " " the accuracy: 0.7811550151975684 the Other indicators: - Precision recall F1-score support in the died 0.91 0.78 0.84 236 the survived 0.58 0.80 0.67 Abo

", Classification_report (Gbc_y_predict, Y_test, target_names=['died','survived']))103 104 " " the Single decision tree accuracy: 0.7811550151975684106 Other indicators:107 Precision recall F1-score support108 109 died 0.91 0.78 0.84 236 the survived 0.58 0.80 0.67111 the avg/total 0.81 0.78 0.79 329113 the Random forest accuracy: 0.78419452887538 the Other indicators: the Precision recall F1-score support117 118 died 0.91 0.78 0.84 237119 survived 0.58 0.80 0.68 - 121 avg/total 0.82 0.78 0.79

-za-z]"," ", Sent.lower (). Strip ()). Split () in sentences.append (temp) - to returnsentences + - #The sentences in the long news are stripped out for training . thesentences = [] * forIinchx: $Sentence_list =news_to_sentences (i)Panax NotoginsengSentences + =sentence_list - the + #Configure the dimension of the word vector ANum_features = 300 the #the frequency of the words that are to be considered +Min_word_count = 20 - #number of CPU cores used in parallel computing $Num_workers =