algorithm (LSH) solves the problem of mechanical similarity of text (I, basic principle)The R language implements the ︱ local sensitive hashing algorithm (LSH) to solve textual mechanical similarity problems (two. Textreuse introduction)The four parts of the mechanical-similar Python version:Lsh︱python realization of locally sensitive random projection forest--lshforest/sklearn (i.)Lsh︱python implementing a locally sensitive hash--lshash (ii)Similari
Call Python's sklearn to implement the logistic reression algorithmFirst of all, how to implement, where the import database and class, method of the relationship, not very clear before, now know ...From numpy Import * from sklearn.datasets import load_iris # import datasets# load the Dataset:irisiris = Load_iris () Samples = Iris.data#print Samples target = iris.target # import the Logisticregressionfrom Sklearn.linear_model import Lo Gisticregre
[[P1,P2],[P3,P4] ...]Correct rate Scoreneighbors.KNeighborsClassifier.score(X, y, sample_weight=None)We typically divide our training datasets into two categories, one for learning and training models, and one for testing, and this kinetic energy is the ability to test after learning to see the accuracy.Practical examplesFirst we take the example of film splitting in the KNN algorithm in the Machine learning series. We implemented a KNN classifier in that series, taking the Euclidean distance,
challenge, I believe there are many people like me. Say more, back to, the previous several blog mentioned, feature selection, regularization, as well as unbalanced data and outlier classification problems, but also related to matplotlib in the method of drawing. Today we will talk about how to choose the super parameters in the modeling process: Grid search + Cross validation. In this paper, we first give a sample of SVM in Sklearn, then explain how
Tags: datasets linear alt load gets get share picture learn DataSet fromSklearnImportDatasets fromSklearn.linear_modelImportlinearregression#to import data from the Boston rate provided by SklearnLoaded_data =Datasets.load_boston () x_data=Loaded_data.datay_data=Loaded_data.targetmodel= Linearregression ()#model with linear regression yoModel.fit (x_data,y_data)#first show the previous 4Print(Model.predict (X_data[:4,:]))Print(Y_data[:4])Sklearn also
Logical regression:
It can be used for probability prediction and classification, and can be used only for linear problems. by calculating the probability of the real value and the predicted value, and then transforming into the loss function, the
The discussion about the double clustering.
Data that produces a double cluster can use a function,
Sklearn.datasets.make_biclusters (Shape = (row, col), n_clusters, noise, \
Shuffle, Random_state)
N_clusters Specifies the number of cluster data
Reduced dimension Reference URL http://dataunion.org/20803.html"Low Variance filter" requires normalization of the data first"High correlation filtering" thinks that when two columns of data change in a similar trend, they contain similar
Text mining paper did not find a unified benchmark, had to run the program, passing through the predecessors if you know 20newsgroups or other useful common data set classification (preferably all class classification results, All or take part of
1. What is k nearest neighbor
Popular Will, if I were a sample, the KNN algorithm would be to find a few recent samples, see what categories they all belong to, and then select the category with the largest percentage of their category. KNN is the
1. Convert the data in the dictionary format to a feature .
The premise: The data is stored in a dictionary format, by calling the Dictvectorizer class to convert it to a feature, for a variable with a character value of type, automatically
1. One hot encoder
Sklearn.preprocessing.OneHotEncoder
One hot encoder can encode not only the label, but also the categorical feature:
>>> from sklearn.preprocessing import onehotencoder
>>> enc = onehotencoder ()
>>> Enc.fit ([[0, 0, 3], [1, 1,
The main tasks of data preprocessing are:
First, data preprocessing
1. Data cleaning
2. Data integration
3. Data Conversion
4. Data reduction
1. Data cleaningReal-world data is generally incomplete, noisy, and inconsistent. The data cleanup
Machine Learning: ROC curve of classification algorithm performance indicators and performance indicator roc
Before introducing the ROC curve, let's talk about the confusion matrix and two formulas, because this is the basis for ROC curve calculation.
1. Example of confusion matrix (whether to click advertisement ):
Note:
TP: the prediction results are consistent with the actual results, and all click ads.
FP: The prediction result is clicked, but the actual situation is not clicked.
FN: The pr
This article introduces the content of the detailed classification evaluation indicators and regression evaluation indicators and Python code implementation, has a certain reference value, now share to everyone, there is a need for friends to refer to.
1. Concept
Performance measurement (evaluation) indicators, the main divided into two major categories:1) Classification Evaluation Index (classification), main analysis, discrete, integer. Specific indicators include accuracy (accuracy rate), pre
added in order to prevent a conditional probability of 0, thus the whole P (x| Y) = P (x1| Y) P (x2| Y) ... P (xn| Y) product is 0.
Instance Demo classifies a message as a data collection from the University of California, Irvine, http://archive.ics.uci.edu/ml/datasets/spambase Spambase data Format description is as follows: English, I do not explain (mainly to explain the difficulty,-_-. Sorry to determine the quality of the classification model, you can calculate the
= roc_curve (credit ["paid"], credit ["model_score"]) idx = numpy. where (fpr> 0.20) [0] [0] # select a threshold with a false positive rate of 0.2 for the following print ('fpr: 100') print ('tpr: {}'. format (tpr [idx]) print ('threashold :{}'. format (thres [idx]) # use false positive rate as the X axis, and use True rate as the Y axis to plot plt. plot (fpr, tpr) plt. xlabel ('fpr') plt. ylabel ('tpr ') plt. show ()
It indicates that when the threshold is set to 0.38, FPR = 0.2, TPR = 0.93
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