python machine learning cookbook chris albon

Rate the Fl-score the Support the 98 Logistic regression accuracy rate: 0.9707602339181286 About Other indicators of logistic regression: - Precision recall F1-score support101 102 benign 0.96 0.99 0.98103 Malignant 0.99 0.94 0.96104 the avg/total 0.97 0.97 0.97 171106 107 estimation accuracy of stochastic parameters: 0.9649122807017544108 Other indicators of stochastic parameter estimation:109 Precision recall F1-score support the 111 benign 0.97 0.97 0.97 the malignant 0.96 0.96 0.96113 th

are slightly different, and many very small elements are left in the matrix, which results from the computer processing error. Enter the following command to get the error value:>>> MyEye = Randmat*invrandmat>>> Myeye-eye (4)Matrix ([[ 0.00000000e+00, -4.44089210e-16, -4.44089210e-16, -3.33066907E-16], [ -8.88178420e-16, 2.22044605e-16, 0.00000000e+00, 5.55111512E-17], [ 4.44089210e-16, 0.00000000e+00, 0.00000000e+00, -5.55111512E-17],

]) $self.errors_=[] - - for_inchRange (self.n_iter): theerrors=0 - forXi,targetinchzip (x, y):Wuyi #calculates the error between the forecast and the actual value multiplied by the learning rate theupdate=self.eta* (target-Self.predict (xi)) -self.w_[1:]+=update*XI WuSelf.w_[0]+=update*1 -Errors + = Int (update!=0) About self.errors_.append (Errors) $ return Self - - #define the p

column of the BCW dataset before applying it to a linear classifier. In addition, we want to compress the original 30 dimension features into 2 dimensions, which is given to the PCA.Before we all performed an operation at each step, we now learn to connect Standardscaler, PCA, and logisticregression together using pipelines:The pipeline object receives a list of tuples as input, each tuple has the first value as the variable name, and the second element of the tuple is transformer or estimator

print ' Best Feature index:\t ', bestfeatureindex print ' Best thresh old:\t\t ', Bestthreshold ' return{' Dim ': Bestfeatureindex,' Thresh ': Bestthreshold,' accuracy ': Bestaccuracy} def Apply_model(Features,labels,model):Prediction = (features[:,model[' Dim ']] > model[' Thresh '])returnPrediction#-----------Cross validation-------------Error =0.0 forEiinchRange (len (irisfeatures)):# Select All and the one at position ' ei ':Training = Np.ones (len (irisfeatures), bool) Training[ei] =Fal

matrix matrices, and the column represents the feature, where the percentage represents the variance ratio of the number of features required before taking the default to 0.9" "defPCA (datamat,percentage=0.9): #averaging for each column, because the mean value is subtracted from the calculation of the covarianceMeanvals=mean (datamat,axis=0) meanremoved=datamat-meanvals#CoV () Calculating varianceCovmat=cov (meanremoved,rowvar=0)#using the Eig () method in the module linalg for finding eigen

criteria for the end of recursion are:1: All class tags are exactly the same, return the class label (this is not nonsense, all the same, the class of the hair)2: Using all the groupings or not dividing the dataset into groups that contain only unique categories, since we cannot return a unique one, then we are represented by a wave. Is our majority voting mechanism above, returning the category with the most occurrences. This is not the NPC,.The code is as follows:People can not understand the

Naive Bayesian algorithm is simple and efficient, and it is one of the first ways to deal with classification problems. With this tutorial, you'll learn the fundamentals of naive Bayesian algorithms and the step-by-step implementation of the Python version. Update: View subsequent articles on naive Bayesian use tips "Better Naive bayes:12 tips to get the Most from the Naive Bayes algorithm"Naive Bayes classifier, Matt Buck retains part of the copyri

another feature of the library Numarray of the same nature, and added other extensions and developed the NumPy. NumPy is open source and co-maintained by many collaborators to develop.2 Matplotlib Brief IntroductionMatplotlib is a library of very similar MATLAB environments that generate publishing quality data. The user can output the data in a pop-up window as a raster format (PNG, TIFF, JPG) or as a vector file (e.g. EPS, PS). Matlab users are familiar with the graphics types and syntax for

, but please disregard its rationality)The branch of the decision tree for the two-value logic of "non-" is quite natural. In this data set, how is height and weight continuous value?Although this is a bit of a hassle, it's not a problem, it's just a matter of finding the intermediate points that divide these successive values into different intervals, which translates into two-value logic.The task of this decision tree is to find some critical values in height and weight, classify their sample

System: OS X 10.11.6 The MAC system has its own Python2.7, using the Easy_install command with its own system to install the modules online. If you need to use the PYTHON3 environment, python3.5 is invoked at the terminal input Python3 after installing the Python3.5.1, view Python version Python 2, install NumPyNumPy is a Python package. It represents "Numer

bestfeatue in creating is:0the bestfeatue in creating are : 0{' no surfacing ': {0: ' No ', 1: {' flippers ': {0: ' No ', 1: ' Yes '}}}It is best to increase the classification function using the decision treeAlso because building a decision tree is time-consuming, because it is best to serialize the constructed tree through Python's pickle and save the object inOn the disk, and then read it when neededdef classify (Inputtree,featlabels,testvec): firststr = Inputtree.keys () [0] seconddic

), + Ss_y.inverse_transform (dis_knr_y_predict))) the Print("the average absolute error of the distance weighted K-nearest neighbor regression is:", Mean_absolute_error (Ss_y.inverse_transform (y_test), - Ss_y.inverse_transform (dis_knr_y_predict))) $ the " " the the default evaluation value for the average K-nearest neighbor regression is: 0.6903454564606561 the the r_squared value of the average K-nearest neighbor regression is: 0.6903454564606561 the Mean square error of average K nearest ne

) Seeking a=x *θ (2) Ask E=g (A)-y(3) Request (A for step)3, algorithm optimization--stochastic gradient methodThe gradient rise (descent) algorithm needs to traverse the entire data set each time the regression coefficients are updated, which is good when dealing with about 100 datasets, but if there are billions of samples and thousands of features, the computational complexity of the method is too high. An improved method is to update the regression coefficients with only one sample point at

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This article is a combination of the recommended algorithm and SVD in conjunction with machine learning combat.Any matrix can be decomposed into the form of SVD.In fact, the SVD meaning is to use the transformation of the feature space to map the data, the following will be devoted to the basic concept of SVD, first give a python, here first give a simple matrix,

(i) Understanding decision Trees1, decision tree Classification principleRecent surveys have shown that decision trees are also the most frequently used data mining algorithms, and the concept is simple. One of the most important reasons why a decision tree algorithm is so popular is that the user does not have to understand the machine learning algorithm, nor does it have to delve into how it works. Intuit

): # Extend the Input feature vector as a feature matrix linenum = featurematrix.shape[0] featurematrixin = Np.tile ( Featurevectorin, (linenum,1)) # Calculate the Euclidean distance between the matrix Diffmatrix = featurematrixin -Featurematrix Sqdiffmatrix = Diffmatrix * * 2 Distancevaluearray = Sqdiffmatrix.sum (Axis=1) Distancevaluearray = Distancevaluearray * * 0.5 return DistancevaluearrayUsed in the numpy of the more distinctive things. The practice is to first

Environment:Win7 64-bit systemFirst step: install Python1, download python2.7.3 64-bit MSI version (here Select a lot of 2.7 of the other higher version resulting in the installation of Setuptools failure, do not know what the reason, for the time being, anyway, choose this version can be)2, install Python, all next point down.3, configure the environment variables, I am the default to add C:\Python path ca

classes in the data. - -Many, many more ... the the a total of 150 data samples the evenly distributed over 3 subspecies the 4 petals per sample, calyx shape Description - " " the the " " the 2 dividing the training set and the test set94 " " theX_train, X_test, y_train, y_test =train_test_split (Iris.data, the Iris.target, thetest_size=0.25,98Random_state=33) About - " "101 3 K Nearest Neighbor Classifier learning model and prediction102 " "10