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How to access the correct `this` inside a callback?
... that adds meaning, or some preceding and following information that gives extra meaning. The term "context" is used in ECMAScript to refer to execution context, which is all the parameters, scope, and this within the scope of some executing code.
This is shown in ECMA-262 section 10.4.2:
Set the T...
Is Java “pass-by-reference” or “pass-by-value”?
... easily confuse many beginners.
It goes like this:
public static void main(String[] args) {
Dog aDog = new Dog("Max");
Dog oldDog = aDog;
// we pass the object to foo
foo(aDog);
// aDog variable is still pointing to the "Max" dog when foo(...) returns
aDog.getName().equals("...
What to do Regular expression pattern doesn't match anywhere in string?
...lt;quote>
}{$+{BODY}}six;
return $_;
}
sub descape {
my $string = $_[0];
for my $_ ($string) {
s{
(?<! % )
% ( \p{Hex_Digit} {2} )
}{
chr hex $1;
}gsex;
s{
& \043
( [0-9]+ )
...
Is the C# static constructor thread safe?
... for each T.
}
}
EDIT:
Here is the demonstration:
static void Main(string[] args)
{
var obj = new Foo<object>();
var obj2 = new Foo<string>();
}
public class Foo<T>
{
static Foo()
{
System.Diagnostics.Debug.WriteLine(String.Format("Hit {0}", typeof...
how can you easily check if access is denied for a file in .NET?
...ened after the required attempts</returns>
public FileStream TryOpen(string filePath, FileMode fileMode, FileAccess fileAccess,FileShare fileShare,int maximumAttempts,int attemptWaitMS)
{
FileStream fs = null;
int attempts = 0;
// Loop allow multiple attempts
while (true)
...
How to make a chain of function decorators?
...udes the function functools.wraps(), which copies the name, module, and docstring of the decorated function to its wrapper.
(Fun fact: functools.wraps() is a decorator! ☺)
# For debugging, the stacktrace prints you the function __name__
def foo():
print("foo")
print(foo.__name__)
#outputs:...
How to check if a map contains a key in Go?
... the value of "foo" from the map or a "zero value" (in this case the empty string) and ok will receive a bool that will be set to true if "foo" was actually present in the map
evaluates ok, which will be true if "foo" was in the map
If "foo" is indeed present in the map, the body of the if stateme...
Get a filtered list of files in a directory
...ead for very large data sets, but for listing a directory and other simple string filtering tasks, list comprehensions lead to more clean documentable code.
The only thing about this design is that it doesn't protect you against making the mistake of passing a string instead of a list. For example...
How to deal with a slow SecureRandom generator?
...RNG, do something like this:
SecureRandom.getInstance("SHA1PRNG");
What strings are supported depends on the SecureRandom SPI provider, but you can enumerate them using Security.getProviders() and Provider.getService().
Sun is fond of SHA1PRNG, so it's widely available. It isn't especially fast ...
Need to understand the usage of SemaphoreSlim
...n (i.e., no FIFO priorities).
When a teacher is around, she "releases" an extra row of 5 footprints on the other side of the corridor such that 5 more kids can play in the room at the same time.
It also has the same "pitfalls" of SemaphoreSlim...
If a kid finishes playing and leaves the room with...