Popular recipes by Sean Ross

Fresh function defaults (Python)

2004-09-04T05:30:54-07:00

Python recipe 303440 by Sean Ross .

This recipe provides a decorator for keeping mutable default function values fresh between calls.

A tidy property idiom (Python)

2003-08-01T14:57:43-07:00

Python recipe 205183 by Sean Ross (oop). Revision 5.

This recipe suggests an idiom for property creation that avoids cluttering the class space with get/set/del methods that will not be used directly.

sample with replacement (Python)

2004-03-08T00:21:23-08:00

Python recipe 273085 by Sean Ross (algorithms). Revision 3.

For taking k random samples (with replacement) from a population, where k may be greater than len(population).

Combining simple and specific property creation (Python)

2003-11-28T13:16:44-08:00

Python recipe 252180 by Sean Ross (oop).

This recipe provides a function that will automate simple property creation, while allowing its users to provide specific fget/fset/fdel methods.

a simple genetic algorithm (Python)

2008-01-18T19:51:11-08:00

Python recipe 199121 by Sean Ross (algorithms).

Dictionary of Function Parameters (Python)

2004-04-28T23:19:59-07:00

Python recipe 201195 by Sean Ross (shortcuts). Revision 2.

This recipe is based on http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/157572.

Calling parameters() inside a function will return that function's parameters as a dictionary. The dictionary does not include varargs, since *varargs items do not have a "name" that can be used as a key. However, *varkw is added to the dictionary, as an update.

There are three optional parameters that can be used to filter the information returned.

Determining the current functions name (at the time it is called) (Python)

2003-05-22T01:30:08-07:00

Python recipe 200892 by Sean Ross (debugging). Revision 4.

whoaminow() can be used inside a function to determine, at the time it is called, the name under which that function has been invoked.

NOTE: This solution is extremely brittle and provides very limited utility, as it stands. However, it does serve to highlight an interesting avenue for introspection, namely, the dis module.

Automating simple property creation (Python)

2003-09-07T04:49:13-07:00

Python recipe 157768 by Sean Ross (oop).

The following are a set of functions for creating simple properties - like Ruby's attr_reader, attr_writer, and attr_accessor.

If, inside a class definition, you write:

&nbsp &nbsp &nbsp &nbsp attribute(foo=1, bar=2)

simple properties named 'foo' and 'bar' are created for this class. Also, private instance variables '__foo' and '__bar' will be added to instances of this class.

By "simple properties", I mean something like the following:

&nbsp &nbsp &nbsp &nbsp ''' assume we're inside a class definition and &nbsp &nbsp &nbsp &nbsp self.__foo and self.__bar have been instantiated. &nbsp &nbsp &nbsp &nbsp ''' &nbsp &nbsp &nbsp &nbsp def get_foo(self): &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp return self.__foo &nbsp &nbsp &nbsp &nbsp def set_foo(self, value): &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp self.__foo = value &nbsp &nbsp &nbsp &nbsp def del_foo(self): &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp del self.__foo &nbsp &nbsp &nbsp &nbsp def get_bar(self): &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp return self.__bar &nbsp &nbsp &nbsp &nbsp def set_bar(self, value): &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp self.__bar = value &nbsp &nbsp &nbsp &nbsp def del_bar(self): &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp &nbsp del self.__bar &nbsp &nbsp &nbsp &nbsp foo = property(fget=get_foo, fset=set_foo, fdel=del_foo, doc="foo") &nbsp &nbsp &nbsp &nbsp bar = property(fget=get_bar, fset=set_bar, fdel=del_bar, doc="bar")