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Assignment inside lambda expression in Python
...asons. For example, we will be able to write the following:
import sys
say_hello = lambda: (
message := "Hello world",
sys.stdout.write(message + "\n")
)[-1]
say_hello()
In Python 2, it was possible to perform local assignments as a side effect of list comprehensions.
import sys
say_hell...
Why would you use an ivar?
...d by the compiler may involve another C function call to the functions objc_getProperty/objc_setProperty, as these will have to retain/copy/autorelease the objects as needed and further perform spinlocking for atomic properties where necessary. This can easily get very expensive and I'm not talking ...
Most Pythonic way to provide global configuration variables in config.py? [closed]
...ot",
"pass": "secret",
"tables": {
"users": "tb_users"
}
# etc
}
}
You'd access the values as follows:
config["mysql"]["tables"]["users"]
If you are willing to sacrifice the potential to compute expressions inside your config tree, you could use...
How to trigger event when a variable's value is changed?
...e you want to create a property.
public int MyProperty
{
get { return _myProperty; }
set
{
_myProperty = value;
if (_myProperty == 1)
{
// DO SOMETHING HERE
}
}
}
private int _myProperty;
This allows you to run some code any time the pr...
Get hours difference between two dates in Moment Js
...ent('2016-06-06T22:34:56'); var b = moment('2016-06-06T21:03:55'); var diff_s = a.diff(b, 'seconds'); console.log(moment.utc(moment.duration(diff_s, "seconds").asMilliseconds()).format("hh:mm:ss"))
– user632905
Jul 12 at 15:35
...
How to use the PI constant in C++
...ially older) platforms (see the comments below) you might need to
#define _USE_MATH_DEFINES
and then include the necessary header file:
#include <math.h>
and the value of pi can be accessed via:
M_PI
In my math.h (2014) it is defined as:
# define M_PI 3.1415926535897932384...
Pointers in Python?
...putations, possibilities would include:
class Form(object):
...
def __getattr__(self, name):
return self.data[name]
and
class Form(object):
...
@property
def data(self):
return self.__dict__
The presence of .value suggests picking the first form, plus a kind-of-use...
What is the best way to prevent session hijacking?
...
// Collect this information on every request
$aip = $_SERVER['REMOTE_ADDR'];
$bip = $_SERVER['HTTP_X_FORWARDED_FOR'];
$agent = $_SERVER['HTTP_USER_AGENT'];
session_start();
// Do this each time the user successfully logs in.
$_SESSION['ident'] = hash("sha256", $aip . $bip . $a...
Forward an invocation of a variadic function in C
...
If you don't have a function analogous to vfprintf that takes a va_list instead of a variable number of arguments, you can't do it. See http://c-faq.com/varargs/handoff.html.
Example:
void myfun(const char *fmt, va_list argp) {
vfprintf(stderr, fmt, argp);
}
...
How to solve Operator '!=' cannot be applied to operands of type 'T' and 'T' [duplicate]
...
public class Test<T>
{
public T Value
{
get => _Value;
set
{
// operator== is undefined for generic T; EqualityComparer solves this
if (!EqualityComparer<T>.Default.Equals(_Value, value))
{
_Valu...