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Creating a singleton in Python
...mple implementation:
class Singleton(type):
_instances = {}
def __call__(cls, *args, **kwargs):
if cls not in cls._instances:
cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
return cls._instances[cls]
class Logger(object):
__meta...
super() raises “TypeError: must be type, not classobj” for new-style class
...pe(OldStyle()) is the instance type, which does inherit from object. Basically, an old-style class just creates objects of type instance (whereas a new-style class creates objects whose type is the class itself). This is probably why the instance OldStyle() is an object: its type() inherits from ob...
How to kill a process running on particular port in Linux?
...TIME_WAIT state after the parent process is killed. The OS will then eventually completely close the port after about 60 seconds. It means that you can't reuse the port for at least 60 seconds (unless you give the reuse option to the socket).
– Mark Lakata
Sep ...
Python circular importing?
... of it) for the first time, the code inside the module is executed sequentially like any other code; e.g., it is not treated any differently that the body of a function. An import is just a command like any other (assignment, a function call, def, class). Assuming your imports occur at the top of th...
What's the common practice for enums in Python? [duplicate]
...(names.split()):
setattr(self, name, number)
>>> foo = Enumeration("bar baz quux")
>>> foo.quux
2
You can also just use class members, though you'll have to supply your own numbering:
>>> class Foo(object):
bar = 0
baz = 1
quux...
How to get POSTed JSON in Flask?
...
First of all, the .json attribute is a property that delegates to the request.get_json() method, which documents why you see None here.
You need to set the request content type to application/json for the .json property and .get_jso...
How do you see the entire command history in interactive Python?
...s there an option like the --history option in bash shell, which shows you all the commands you've entered so far?
10 Answe...
How do I write unit tests in PHP? [closed]
...u have the following function in a file called lib.php:
<?php
function foo($bar)
{
return $bar;
}
?>
Really simple and straight forward, the parameter you pass in, is returned. So let's look at a test for this function, we'll call the test file foo.phpt:
--TEST--
foo() function - A basic...
An example of how to use getopts in bash
I want to call myscript file in this way:
7 Answers
7
...
Elegant ways to support equivalence (“equality”) in Python classes
When writing custom classes it is often important to allow equivalence by means of the == and != operators. In Python, this is made possible by implementing the __eq__ and __ne__ special methods, respectively. The easiest way I've found to do this is the following method:
...