python-2.x

I would've expected Python's keys method to return a set instead of a list. Since it most closely resembles the kind of guarantees that keys of a hashmap would give. Specifically, they are unique and not sorted, like a set. However, this method returns a list: >>> d = {} >>> d.keys().__class__ <type 'list'> Is this just a mistake in the Python API or is there some other reason I am missing? NPE One reason is that dict.keys() predates the introduction of sets into the language. Note that the return type of dict.keys() has changed in Python 3: the function now returns a "set-like" view rather

There are many ways to include Python 3.x features in Python 2.x , so code of Python 2.x scripts could be easily converted into Python 3.x in the future. One of these examples is replacing print statement with print() function: >>> from __future__ import print_function Is there any list or resource that could give one some ideas how to make Python 2.x code as close to Python 3.x as possible? Could you give examples of other useful imports or definitions that can make Python 2.x look and behave more like Python 3.x ? Lets assume we have the latest Python 2.x (2.7.2 at the moment, I believe) at

I recently came across a syntax I never seen before when I learned python nor in most tutorials, the .. notation, it looks something like this: f = 1..__truediv__ # or 1..__div__ for python 2 print(f(8)) # prints 0.125 I figured it was exactly the same as (except it's longer, of course): f = lambda x: (1).__truediv__(x) print(f(8)) # prints 0.125 or 1//8 But my questions are: How can it do that? What does it actually mean with the two dots? How can you use it in a more complex statement (if possible)? This will probably save me many lines of code in the future...:) Paul Rooney What you have is

I would like you to consider the following code: def func(alist): if len(alist) == 1: return arg * 2 for item in alist: yield item * 2 When I run it, I get this error: SyntaxError: 'return' with argument inside generator Now, I realize that I cannot do this. However, I would like to know why. What exactly is going on behind the scenes that is causing Python to throw the SyntaxError ? Python has to decide whether a function is a generator at bytecode compilation time. This is because the semantics of generators say that none of the code in a generator function runs before the first next call;

I am trying to create an AbstractClass using both abc.ABCMeta and QObject as parents and cannot seems to make it work. Here is the Base class init. I have Pyqt5 and python 2.7 pyqtWrapperType = type(QObject) class ParamsHandler(abc.ABCMeta, pyqtWrapperType): def __init__(self, device_model, read_only=False): super(ParamsHandler, self).__init__() self.cmd_to_get_data = None self.device_model = device_model class ConfigParamsHandler(ParamsHandler): def __init__(self, device_model): super(ConfigParamsHandler, self).__init__(device_model) self.cmd_to_get_data = Commands.CONFIG_PARAMS I get a