数据集参见：
http://www-stat-class.stanford.edu/~tibs/ElemStatLearn/data.html
Bone Mineral Density: Info Data
Countries: Info Data
Galaxy: Info Data
Marketing: Info Data
Mixture Simulation: Info Data
NCI (microarray): Info Data
Ozone: Info Data
Phoneme: Info Data
Prostate: Info Data
Skin of the Orange (Section 12.3.4): Info Data
South African Heart Disease: Info Data
Spam: Info Data and test set Indicator
For more informations, see the UCI spambase directory.
Vowel: Info, Training and Test data.
Waveform: Info, Training and Test data, and a generating function waveform.S (Splus or R).
ZIP code: Info, gzipped Training and Test data.
Since the training data are somewhat large, you can access the digits separately.
