Fix Python – Accessing class variables from a list comprehension in the class definition

How do you access other class variables from a list comprehension within the class definition? The following works in Python 2 but fails in Python 3:
class Foo:
x = 5
y = [x for i in range(1)]

Python 3.2 gives the error:
NameError: global name ‘x’ is not defined

Trying Foo.x doesn’t work either. Any ideas on how to do this in Python 3?….

Fix Python – Why is ‘x’ in (‘x’,) faster than ‘x’ == ‘x’?

>>> timeit.timeit(“‘x’ in (‘x’,)”)
0.04869917374131205
>>> timeit.timeit(“‘x’ == ‘x'”)
0.06144205736110564

Also works for tuples with multiple elements, both versions seem to grow linearly:
>>> timeit.timeit(“‘x’ in (‘x’, ‘y’)”)
0.04866674801541748
>>> timeit.timeit(“‘x’ == ‘x’ or ‘x’ == ‘y'”)
0.06565782838087131
>>> timeit.timeit(“‘x’ in (‘y’, ‘….

Fix Python – Why are some float < integer comparisons four times slower than others?

When comparing floats to integers, some pairs of values take much longer to be evaluated than other values of a similar magnitude.
For example:
>>> import timeit
>>> timeit.timeit(“562949953420000.7 < 562949953421000") # run 1 million times 0.5387085462592742 But if the float or integer is made smaller or larger by a certain amount, the compariso....

Fix Python – Are dictionaries ordered in Python 3.6+?

Dictionaries are insertion ordered as of Python 3.6. It is described as a CPython implementation detail rather than a language feature. The documentation states:

dict() now uses a “compact” representation pioneered by PyPy. The memory usage of the new dict() is between 20% and 25% smaller compared to Python 3.5. PEP 468 (Preserving the order of *….

Fix Python – How does the @property decorator work in Python?

I would like to understand how the built-in function property works. What confuses me is that property can also be used as a decorator, but it only takes arguments when used as a built-in function and not when used as a decorator.
This example is from the documentation:
class C:
def __init__(self):
self._x = None

def getx(self):
….