Feature Selection in MATLAB

Question

I have a dataset for text classification ready to be used in MATLAB. Each document is a vector in this dataset and the dimensionality of this vector is extremely high. In th

Answer 1

Feature selection depends on the specific task you want to do on the text data.

One of the simplest and crudest method is to use Principal component analysis (PCA) to reduce the dimensions of the data. This reduced dimensional data can be used directly as features for classification.

See the tutorial on using PCA here:

http://matlabdatamining.blogspot.com/2010/02/principal-components-analysis.html

Here is the link to Matlab PCA command help:

http://www.mathworks.com/help/toolbox/stats/princomp.html

Using the obtained features, the well known Support Vector Machines (SVM) can be used for classification.

http://www.mathworks.com/help/toolbox/bioinfo/ref/svmclassify.html http://www.autonlab.org/tutorials/svm.html