Nurdok

class SingletonType(type):

    def __call__(cls, *args, **kwargs):
        try:
            return cls.__instance
        except AttributeError:
            cls.__instance = super(SingletonType, cls).__call__(*args, **kwargs)
            return cls.__instance

Nurdok

>>> seq_x = [1, 2, 3, 4]
>>> seq_y = 'abc'
>>> [(x,y) for x in seq_x for y in seq_y]
1: [(1, 'a'),
 (1, 'b'),
 (1, 'c'),
 (2, 'a'),
 (2, 'b'),
 (2, 'c'),
 (3, 'a'),

Nurdok

>>> result = []
... for x in seq_x:
...     for y in seq_y:
...         result.append((x,y))
>>> result
2: [(1, 'a'),
 (1, 'b'),
 (1, 'c'),
 (2, 'a'),
 (2, 'b'),

Nurdok

>>> seq = ['abc', 'def', 'g', 'hi']
... [y for x in seq if len(seq) > 1 for y in x if y != 'e']
['a', 'b', 'c', 'd', 'f', 'g', 'h', 'i']

Nurdok

>>> result = []
... for x in seq:
...     if len(seq) > 1:
...         for y in x:
...             if y != 'e':
...                 result.append(y)
... result
['a', 'b', 'c', 'd', 'f', 'g', 'h', 'i']

Nurdok

 def singleton(cls):
     instances = {}

     def getinstance():
         if cls not in instances:
             instances[cls] = cls()
         return instances[cls]

     return getinstance

Nurdok

Python Number Conversion Chart

From	To	Expression

Nurdok

"""TODO: A docstring"""


class Bean(type):
    def __init__(cls, name, bases, dct):
        def init(self, *args, **kwargs):
            for attr, arg in zip(cls._attrs, args):
                setattr(self, attr, arg)
            for name, value in kwargs.iteritems():
                setattr(self, name, value)

Nurdok

def withenv(name):
    def inenv(func):
        def new_func(*args, **kwargs):
            print 'withenv {}'.format(name)
            func(*args, **kwargs)
        return new_func
    return inenv

def withenv_byname(func):
    def new_func(self, *args, **kwargs):

Nurdok

>>> class Works(object):
...     a = 1
...     b = [a + x for x in range(10)]
>>> Works.a
0: 1
>>> Works.b
1: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]
>>> class DoesntWork(object):
...     a = 1
...     b = (a + x for x in range(10))