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print call stack in C or C++
...ing stack frame). To translate these to something of use, there's backtrace_symbols(3).
Pay attention to the notes section in backtrace(3):
The symbol names may be unavailable
without the use of special linker
options.
For systems using the GNU linker, it is necessary to use the
...
What are “first class” objects?
...ally has a fairly rich and sophisticated interface.
>>> dir(2)
['__abs__', '__add__', '__and__', '__class__', '__cmp__', '__coerce__', '__delattr__', '__div__', '__divmod__', '__doc__', '__float__', '__floordiv__', '__getattribute__', '__getnewargs__', '__hash__', '__hex__', '__index__', '...
#define macro for debug printing in C?
...
If you use a C99 or later compiler
#define debug_print(fmt, ...) \
do { if (DEBUG) fprintf(stderr, fmt, __VA_ARGS__); } while (0)
It assumes you are using C99 (the variable argument list notation is not supported in earlier versions). The do { ... } while (0...
Why exactly is eval evil?
...estion is not specific to LISP. Here is an answer on the same question for PHP, and it applies to LISP, Ruby, and other other language that has an eval:
The main problems with eval() are:
Potential unsafe input. Passing an untrusted parameter is a way to
fail. It is often not a trivial...
Python __str__ versus __unicode__
Is there a python convention for when you should implement __str__() versus __unicode__() . I've seen classes override __unicode__() more frequently than __str__() but it doesn't appear to be consistent. Are there specific rules when it is better to implement one versus the other? Is it ne...
Python extending with - using super() Python 3 vs Python 2
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super() (without arguments) was introduced in Python 3 (along with __class__):
super() -> same as super(__class__, self)
so that would be the Python 2 equivalent for new-style classes:
super(CurrentClass, self)
for old-style classes you can always use:
class Classname(OldStyleParen...
Is there a Python caching library?
...
From Python 3.2 you can use the decorator @lru_cache from the functools library.
It's a Last Recently Used cache, so there is no expiration time for the items in it, but as a fast hack it's very useful.
from functools import lru_cache
@lru_cache(maxsize=256)
def f(x):
...
How do I plot in real-time in a while loop using matplotlib?
...
Did not work on Win64/Anaconda matplotlib.__version__ 1.5.0. An initial figure window opened, but did not display anything, it remained in a blocked state until I closed it
– isti_spl
Feb 4 '16 at 8:39
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Best practices for API versioning? [closed]
...g platforms/languages commonly used to implement web services (Java, .NET, PHP, Perl, Rails, etc.) allow easy binding of web service end-point(s) to a base URI. This way it's easy to gather and keep a collection of files/classes/methods separate across different API versions.
From the API users PO...
Define a lambda expression that raises an Exception
...
There is more than one way to skin a Python:
y = lambda: (_ for _ in ()).throw(Exception('foobar'))
Lambdas accept statements. Since raise ex is a statement, you could write a general purpose raiser:
def raise_(ex):
raise ex
y = lambda: raise_(Exception('foobar'))
But if...