a simple introduction to python class inheritance
python class (3): private variable, __var or _var
python的私有变量，不能从类之外定义或者访问. _var 和 __var 的区别
python class (4): 只允许添加给定的属性 __slots__
限制class的属性，只允许添加被许可的属性 （slots）
python class (5): 使用装饰器@property来设定属性
python的装饰器(decorator) @property
python class (6): python 2 and python 3 class definition with super()
a short notes from stackoverflow about super() in python2 and python3
python regular expression
python regular expression in text processing
working with text data in sklearn
text analysis to count word frequency, training data and using pipeline to automatic the job
first row partition by var order by the numeric var
SQL: get first row partition by variable B order by the valeue of variable C