Latest recipes tagged "shortcuts"

Yet Another NamedTuple (Python)

2014-08-02T02:56:12-07:00

Python recipe 578918 by Steven D'Aprano (shortcuts).

Yet another look at Raymond Hettinger's excellent "namedtuple" factory. Unlike Raymond's version, this one minimizes the use of exec. In the original, the entire inner class is dynamically generated then exec'ed, leading to the bulk of the code being inside a giant string template. This version uses a regular inner class for everything except the __new__ method.

The Secret Name of List Comprehensions (Python)

2014-04-21T20:09:43-07:00

Python recipe 578865 by He Gu (shortcuts).

Sometimes you want to have a list comprehension refer to itself, but you can't because it isn't bound to a name until after it is fully constructed. However, the interpreter creates a secret name that only exists while the list is being built. That name is (usually) "_[1]", and it refers to the bound method "append" of the list. This is our back door to get at the list object itself.

Solve simultaneous linear equations in two variables (Python)

2012-01-24T14:20:01-08:00

Python recipe 578024 by Anand B Pillai (math, shortcuts, solver).

A function to solve simultaneous equations in two variables.

>>> solve('3*x + 5*y = 29; 12*x - 3*y = 24')
(3.0, 4.0)

(Yet another) Assignment in expression Recipe (Python)

2011-12-17T20:03:26-08:00

Python recipe 577987 by harish anand (expression, shortcuts). Revision 3.

Python does not support assignment in if and while statements such as "if (x=func()):". This is an attempt to bring similar functionality to python by injecting bytecode to all functions and methods in a module. This recipe is inspired from recipes 66061, 202234 and 277940.

namedtuple.abc - abstract base class + mix-in for named tuples (Python)

2011-04-02T02:07:00-07:00

Python recipe 577629 by Jan Kaliszewski (abc, collections, dry, inheritance, namedtuple, shortcuts). Revision 7.

If you need

to define named tuple subclasses (including reusable abstract ones), adding/overriding some methods, in a convenient way;
to have the named tuple ABC (abstract base class) for isinstance/issubclass tests;
or simply would like to define your named tuple classes in a class-syntax-based and DRY way (without repeating type names...)

-- this recipe is for you.

Win Shortcuts wrapper. (Python)

2010-07-23T08:10:44-07:00

Python recipe 577321 by Louis RIVIERE (shortcuts, windows, wrapper). Revision 3.

Reads or Creates Windows shortcuts (links).

Method-based URL dispatcher for the Tornado web server (Python)

2009-11-20T11:51:47-08:00

Python recipe 576958 by Dan McDougall (dispatcher, shortcuts, subclass, tornado, url, web). Revision 5.

The MethodDispatcher is a subclass of tornado.web.RequestHandler that will use the methods contained in subclasses of MethodDispatcher to handle requests. In other words, instead of having to make a new RequestHandler class for every URL in your application you can subclass MethodDispatcher and use the methods contained therein as your URLs.

The MethodDispatcher also adds the convenience of automatically passing arguments to your class methods. So there is no need to use Tornado's get_argument() method.

Example

To demonstrate the advantages of using MethodDispatcher I'll present a standard Tornado app with multiple URLs and re-write it using MethodDispatcher...

The standard Tornado way

class Foo(tornado.web.RequestHandler):
    def get(self):
        self.write('foo')

class Bar(tornado.web.RequestHandler):
    def get(self):
        self.write('bar')

class SimonSays(tornado.web.RequestHandler):
    def get(self):
        say = self.get_argument("say")
        self.write('Simon says, %s' % `say`)

application = tornado.web.Application([
    (r"/foo", Foo),
    (r"/bar", Bar),
    (r"/simonsays", SimonSays),
])

The MethodDispatcher way

class FooBar(MethodDispatcher):
    def foo(self):
        self.write("foo")

    def bar(self):
        self.write("bar")

    def simonsays(self, say):
        self.write("Simon Says, %s" % `say`)

application = tornado.web.Application([
    (r"/.*", FooBar)
])

Notes

As you can see from the above example, using the MethodDispatcher can significantly reduce the complexity of Tornado applications. Here's some other things to keep in mind when using the MethodDispatcher:

MethodDispatcher will ignore any methods that begin with an underscore (_). This prevents builtins and private methods from being exposed to the web.
The '/' path is special: It always maps to self.index().
MethodDispatcher does not require that your methods distinquish between GET and POST requests. Whether a GET or POST is performed the matching method will be called with any passed arguments or POSTed data. Because of the way this works you should not use get() and post() in your MethodDispatcher subclasses unless you want to override this functionality.
When an argument is passed with a single value (/simonsays?say=hello) the value passed to the argument will be de-listed. In other words, it will be passed to your method like so: {'say': 'hello'}. This overrides the default Tornado behavior which would return the value as a list: {'say': ['hello']}. If more than one value is passed MethodDispatcher will use the default behavior.

TwitterCmd - Interactive console for twittering (Python)

2009-10-08T02:15:19-07:00

Python recipe 576923 by Anand (command, microblogging, shortcuts, twitter). Revision 4.

TwitterCmd is an interactive console for twitter built on top of python-twitter library. It provides short, easy to remember commands for most twitter actions and provides a one-way interaction with the Python interpreter, exposing its objects to further inspection by the python-twitter API.

DateTimeSyncer with Daylight Savings Time adjustment (Python)

2008-10-31T15:52:18-07:00

Python recipe 576546 by Jack Trainor (shortcuts, sysadmin). Revision 5.

DateTimeSyncer synchronizes computer's current date and time with Daylight Savings adjustment directly without depending on operating system or Python's time.localtime().

This allows programmers to update Daylight Savings Time rules without depending on external updates to OS or Python.

Double-clicking this module will synchronize your computer's date and time on a Windows machine. It can be easily extended other time zones and other operating systems.

Convenient Utility for Making Dictionaries (Python)

2008-07-23T23:55:00-07:00

Python recipe 576373 by Andrew Konstantaras (shortcuts).

This function creates a dictionary containing all of the variables passed as parameters with the variable name being the key and the value of the variable as the value. I use it frequently when passing parameters to another function.

Composable Functions (Python)

2008-07-12T06:08:55-07:00

Python recipe 574458 by Raymond Hettinger (shortcuts).

Decorator for the "f . g" style of function composition familiar to functional programmers.

Automate creation of new Subversion project (Python)

2008-07-09T20:57:15-07:00

Python recipe 574453 by Jack Trainor (shortcuts). Revision 2.

NewSvnProject creates a new Subversion repository, imports new files to it, then checks out those files back to original directory, with a single command or drag'n'drop.

Iterating Over Dates (Python)

2008-06-30T07:51:43-07:00

Python recipe 574441 by Michael Cornelius (shortcuts).

Iterate over a range of dates, [begin, end), day by day. By using datetime objects, rather than date object, it is possible to iterate over smaller time-granularities if desired.

PyGoogle (Python)

2008-06-06T16:46:38-07:00

Python recipe 573447 by Erik Anderson (shortcuts).

PyGoogle searches google. The google search engine uses 'http://www.google.com/search?hl=en&q=' plus whatever you are searching and replaces the spaces with '+' signs.

Create single-file executables for windows (Python)

2008-03-31T09:02:29-07:00

Python recipe 552749 by Chris Somerlot (shortcuts).

This windows batch script uses python and py2exe to create a single, distributable .exe of your python code.

Page through iterable N items at a time (Python)

2008-02-20T18:57:43-08:00

Python recipe 546526 by Wade Leftwich (shortcuts). Revision 2.

Simple generator accepts an iterable L and an integer N and yields a series of sub-generators, each of which will in turn yield N items from L.

Rebind (Python)

2008-02-12T05:37:23-08:00

Python recipe 546510 by Neal Becker (shortcuts).

Temporarily rebind an attribute using contextmanager

RedirectedIO context manager and redirect_io decorator (Python)

2007-11-20T13:50:34-08:00

Python recipe 534166 by Eduardo Padoan (shortcuts). Revision 5.

Use the "with" keyword or a decorator to simplify a bit redirecting IO to a file.

Error logging with context manager and decorator (Python)

2007-09-19T06:52:58-07:00

Python recipe 531821 by Kent Johnson (shortcuts).

A context manager and decorator that wrap common exception trapping and handling code so they may be applied with just a single line of code in the client.

multi_cmp (Python)

2007-09-10T15:00:38-07:00

Python recipe 528941 by Richard Harris (shortcuts).

Comparing over multiples keys is a common task in Python. To make it easier, multi_cmp creates a compound comparison function using the supplied keys and getter.