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How does JavaScript .prototype work?
...reation), and
The standardized accessor (ie. getter/setter) property named __proto__ (similar to 4.)
Object.getPrototypeOf and Object.setPrototypeOf are preferred over __proto__, in part because the behavior of o.__proto__ is unusual when an object has a prototype of null.
An object's [[Prototype...
Unmangling the result of std::type_info::name
... calling function. This should be relatively easy, standard C++ has a type_info class. This contains the name of the typeid'd class/function/etc. but it's mangled. It's not very useful. I.e. typeid(std::vector<int>).name() returns St6vectorIiSaIiEE .
...
How dangerous is it to compare floating point values?
...ince 5 is not a power of 2), as well as irrational results like the square root of anything that's not a perfect square.
Double rounding. On some systems (particularly x86), floating point expressions are evaluated in higher precision than their nominal types. This means that when one of the above t...
How do I get the full path to a Perl script that is executing?
... if the script is at or below the CWD
Additionally, cwd(), getcwd() and abs_path() are provided by the Cwd module and tell you where the script is being run from
The module FindBin provides the $Bin & $RealBin variables that usually are the path to the executing script; this module also provides...
How to disable GCC warnings for a few lines of code
...
TL;DR: If it works, avoid, or use specifiers like __attribute__, otherwise _Pragma.
This is a short version of my blog article
Suppressing Warnings in GCC and Clang.
Consider the following Makefile
CPPFLAGS:=-std=c11 -W -Wall -pedantic -Werror
.PHONY: all
all: puts
fo...
Is it possible to implement a Python for range loop without an iterator variable?
...ou can just live with the extra i variable.
Here is the option to use the _ variable, which in reality, is just another variable.
for _ in range(n):
do_something()
Note that _ is assigned the last result that returned in an interactive python session:
>>> 1+2
3
>>> _
3
F...
“Inner exception” (with traceback) in Python?
...peError("test")
except TypeError, e:
raise MyException(), None, sys.exc_info()[2]
Always do this when catching one exception and re-raising another.
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Format date and time in a Windows batch script
...== " " set day=0%day:~1,1%
echo day=%day%
set datetimef=%year%%month%%day%_%hour%%min%%secs%
echo datetimef=%datetimef%
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Multiple variables in a 'with' statement?
...Unlike the contextlib.nested, this guarantees that a and b will have their __exit__()'s called even if C() or it's __enter__() method raises an exception.
You can also use earlier variables in later definitions (h/t Ahmad below):
with A() as a, B(a) as b, C(a, b) as c:
doSomething(a, c)
...
How can I filter a date of a DateTimeField in Django?
...
Such lookups are implemented in django.views.generic.date_based as follows:
{'date_time_field__range': (datetime.datetime.combine(date, datetime.time.min),
datetime.datetime.combine(date, datetime.time.max))}
Because it is quite verbose there are pla...