Sentiment Classification) because it discards the word order, syntax, and part of semantic information, and becomes a bottleneck affecting performance. The current solutions include:
Use N-Gram syntax features
Take syntax and semantic information into account in the classification task
Model improvement...
Finally, we will introduce the text Representation Method in sklearn and use it to implement a simple text classification.
The dataset we use
, in the algorithm principle, the introduction of a regular term to limit its imbalance rate. Introducing a coefficient, which is its imbalance rate, is approximately 99.7% in this data set. specifically to our model, it has a parameter called isunbanlanced (whether it is unbalanced), set to True, it can automatically detect the imbalance rate.Next, for this unbalanced data set, use some more reliable evaluation metrics. Evaluation indicators with general accuracy is not good, for example, we no
header files of those libraries are also copied to the Include directory under the installation path.At this point, both the Atlas and LAPACK libraries are compiled, where the Lapack library is. A static library, and the Atlas Library is a. so dynamic library. In fact, the dynamic library in Atlas already contains all the symbols and code for the Lapack static library.The following can start compiling the NumPy package that relies on the Lapack and Atlas libraries.3. Compiling the optimized ver
accuracy and recall rate respectively)
ROC and AUC
ROC and AUC are the indicators of the evaluation classifier, and the ABCD of the first graph above is still used, just a little change.
Back to Roc, Roc's full name is called receiver operating characteristic.
ROC concerns two indicators
True Positive Rate (TPR) = TP/[TP + FN], and TPR represents the probability of splitting a positive case
False Positiv
to evaluate the information retrieval system, and the average accuracy map is defined as follows: (of which p,r is the accuracy and recall rate respectively)ROC and AUCThe ROC and AUC are indicators of the evaluation classifier, and the ABCD of the first figure above is still used, just a slight transformation is needed.Returning to Roc, the ROC's full name is called receiver Operating characteristic.ROC Focus on two indicatorsTrue Positive Rate (TPR
fusion of multiple models. "Everything is a ensemble", "Heads top Zhuge Liang", integrated the advantages of different algorithms, to avoid weaknesses, integration of a cow-breaking super model. Many internet companies in a single model after the bottleneck, most will adopt model fusion, more popular is GBDT+LR. Fundamentally, the fusion of multiple models is essentially the output of one model as the input of another model, and the first model acts as the role of feature conversion.
Effect Ass
(oversampling, equivalent to interpolation), lower sampling (downsampling, equivalent to compression), two-stage training (two-phase training), and Threshold (threholding), The threshold value can compensate for the Transcendental category probability. Because global accuracy is difficult to determine in unbalanced data, our main evaluation indicator is the area below the ROC curve (Roc AUC). From our experiment we can draw the following conclusions:
) Call The kNN algorithm in scikit-learn.
# Call The knn algorithm package of scikit from sklearn. neighbors import into def knnClassify (trainData, trainLabel, testData): knnClf = encrypt () # default: k = 5, defined by yourself: KNeighborsClassifier (n_neighbors = 10) knnClf. fit (trainData, ravel (trainLabel) testLabel = knnClf. predict (testData) saveResult(testLabel,'sklearn_knn_Result.csv ') return testLabel
The kNN algorithm package can set its
Sesame HTTP: Remembering the pitfalls of scikit-learn Bayesian text classification, scikit-learn Bayes
Basic steps:
1. Training material classification:
I am referring to the official directory structure:
Put the corresponding text in each directory, a txt file, and a corresponding article: like the following:
Please note that the proportion of all materials should be kept in the same proportion (adjusted according to the training results as appropriate, the ratio is too large, and it is easy
The person who has refined himselfYou are welcome to visit my Pinterest and my blog.This blog all content to study, research and sharing mainly, if need to reprint, please contact me, marked the author and source, and is non-commercial use, thank you!Abstract : This paper mainly describes the semi-supervised algorithm to do text classification (two classification), the main reference is an example of Sklearn-semi-supervised algorithm to do digital rec
generate a high-weight TF-IDF. Therefore, TF-IDF tends to filter out common words and retain important words. For a detailed introduction and examples of TF-IDF, interested students can read this blog. The following describes how to use the TF-IDF in Python. Second, Python computing TF-IDF in Python, scikit-learn package under the calculation of TF-IDF api, the effect is also very good. First install Scikit-clearn. For installation of different systems, see http://scikit-learn.org/stable/instal
Research machine learning will study the classification algorithm, when the model of a classification algorithm is established, the quality of the model needs to be quantified, the most important is the classifier evaluation index. The following is mainly about the indicators of the classifier. (Here, the main is to introduce the two categories of classifier evaluation indicators)Below we can look at the analysis of two types of results:1, accuracy (correct rate)It represents the correct proport
, you can set shrinkage to a smaller value and the number of trees to a larger value.Sample_rate: sample sampling rate. to construct a model with different tendencies, we need to use a subset of the samples for training. Excessive samples may cause more overfitting and local extremely small problems. The sampling ratio is generally 50%-70%.Variable_sample_rate: feature sampling rate, which refers to learning from the features selected from all the features of the sample without using all the fea
is better to embed the RND random number in the-D option, which is more confusing ). When port 80 is detected, the target host replies the SYN/ACK packet back to us (of course, we cannot receive the SYN/ACK packet from other spoofed IP addresses ), it proves that port 80 is open.
3.2 AUC Script Engine
The NMAP scripting engine is one of the most powerful and flexible NMAP functions. It allows you to write your own scripts to perform automated operat
different tendencies, we need to use a subset of the samples for training. Excessive samples may cause more overfitting and local extremely small problems. The sampling ratio is generally 50%-70%.Variable_sample_rate: feature sampling rate, which refers to learning from the features selected from all the features of the sample without using all the features. When one or two features of the trained model are found to be very strong and important, and other features are basically unavailable, you
=[(1+B2) *p*r]/(B2*p+r), the more commonly used is F1.In the information retrieval, the accuracy rate and the recall rate are mutual influence, although both are high is an ideal situation, but in practice, the accuracy is often high, the recall rate is low, or the recall rate is low, but the accuracy rate is high. So in practice often need to make a choice according to the specific situation, for example, the general search situation is to ensure that the recall rate to improve the accuracy rat
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.