Python Implementation of Naive Bayes algorithm and python of Bayesian AlgorithmAdvantages and disadvantages of Naive Bayes Algorithms
Advantage: it is still valid when the data volume is small and can handle multi-category issues
Disadvantage: sensitive to input data preparation methods
Applicable data type: nomina
Python Implementation Method of Naive Bayes algorithm, python of Bayesian Algorithm
This article describes the python Implementation Method of Naive Bayes algorithm. Share it with you for your reference. The specific implementation method is as follows:
Advantages and disadvantages of
Original: (original) Big Data era: a summary of knowledge points based on Microsoft Case Database Data Mining (Microsoft Naive Bayes algorithm)This article is mainly to continue on the two Microsoft Decision Tree Analysis algorithm and Microsoft Clustering algorithm, the use of a more simple analysis algorithm for the target customer group mining, the same use of Microsoft case data for a brief summary. Int
attention to the fact that it is possible to encounter more than one classification probability in the actual operation or the probability of each classification is 0, at this time it is generally random to select a classification as the result. But sometimes it should be treated with care, such as using Bayesian to identify spam, if the probability is the same, even if the two probability difference is not large, it should be treated as non-
Tags: blog http os using ar strong file Data spThis article is mainly to continue on the two Microsoft Decision Tree Analysis algorithm and Microsoft Clustering algorithm, the use of a more simple analysis algorithm for the target customer group mining, the same use of Microsoft case data for a brief summary. Interested students can first refer to the above two algorithms process.Application Scenario IntroductionThe Microsoft Naive
the document model, the Class-condition probability must also be calculated in the document model, and vice versa.
In order to avoid the probability result of class conditions being 0, Laplace probability estimation is adopted.
Preprocessing of the training database
To improve the classification efficiency and accuracy, the training database must be preprocessed. The main preprocessing steps are as follows:
Read all training texts under a certain category
Perform word segmentation for thes
4.7 Example: Using naive Bayesian classifier to derive regional tendencies from personal adsTwo applications were described earlier: 1. Filtering malicious messages from websites; 2. Filter spam.4.7.1 Collecting data: Importing RSS FeedsThe Universal feed parser is the most commonly used RSS library in Python.At the python prompt, enter:Build similar to the Spamt
1, naive Bayesian method, first of all to be clearly used for classification tasks.In machine learning, whenever a classification problem is encountered, all methods focus on two parts: the characteristics of the input vectors to be categorized and the characteristics of each category in the training vector set.The variable is, however, the number of features, the number of categories, and the number of training samples.Naive Bayesian method in dealin
training samples. For example, y = 1 has M1 and training samples have M, then P (y = 1) = m1/m. However, I still cannot figure out the p (x | Y) computation.
Naive Bayes hypothesis: P (x1, x2 ,.., XN | y) = P (X1 | Y )... P (XN | y) (x1, x2 ,..., XN is the component of X, that is, the condition is independent. When I! When J is used, P (XI | y, XJ) = P (XI | Y). If y is specified, the occurrence of Xi is
Probability-based classification method: Naive BayesianBayesian decision theoryNaive Bayes is part of the Bayesian decision theory, so let's take a quick and easy look at Bayesian decision theory before we talk about naive Bayes.The core idea of Bayesian decision-making theory : Choose the decision with the highest probability. For example, we graduate to choose
Example of Naive Bayes algorithm and Bayesian exampleApplication of Bayesian
The famous application of Bayesian classifier for spam filtering is spam filtering, if you want to learn more about this, you can go to hacker and painter or the corresponding chapter in the beauty of mathematics. For the basic implementatio
increases the corresponding value in the word vector instead of just setting the corresponding number to 1.# Converts a group of words into a set of numbers, converting a glossary into a set of vectors: A word set model def Bagofwords2vec (Vocablist, Inputset):# Input: Glossary, a document Returnvec = [0] * Len ( vocablist) for in inputset: if in vocablist: + = 1 return ReturnvecNow that the classifier has been built, the classifier will be used to
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