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Is there a performance gain in using single quotes vs double quotes in ruby?
...t waste your time.
Actual interpolation is a different story, of course. 'foo' will be almost exactly 1 second faster than "#{sleep 1; nil}foo".
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Overload constructor for Scala's Case Classes?
...
Overloading constructors isn't special for case classes:
case class Foo(bar: Int, baz: Int) {
def this(bar: Int) = this(bar, 0)
}
new Foo(1, 2)
new Foo(1)
However, you may like to also overload the apply method in the companion object, which is called when you omit new.
object Foo {
d...
How does the “this” keyword work?
...ains in JavaScript.
Once you start getting used to this, the rules are actually pretty simple. The ECMAScript 5.1 Standard defines this:
§11.1.1 The this keyword
The this keyword evaluates to the value of the ThisBinding of the current execution context
ThisBinding is something that the JavaScrip...
How to add reference to a method parameter in javadoc?
...ding the docs for javadoc there is no such feature.
Don't use <code>foo</code> as recommended in other answers; you can use {@code foo}. This is especially good to know when you refer to a generic type such as {@code Iterator<String>} -- sure looks nicer than <code>Iterator...
change text of button and disable button in iOS
...antage of the fact that they are passed in as an argument to the IBAction calls:
- (IBAction) triggerActionWithSender: (id) sender;
This can be bound to the button and you’ll get the button in the sender argument when the action is triggered. If that’s not enough (because you need to access t...
For loop example in MySQL
...
drop table if exists foo;
create table foo
(
id int unsigned not null auto_increment primary key,
val smallint unsigned not null default 0
)
engine=innodb;
drop procedure if exists load_foo_test_data;
delimiter #
create procedure load_foo_test_...
Recursive Lock (Mutex) vs Non-Recursive Lock (Mutex)
POSIX allows mutexes to be recursive. That means the same thread can lock the same mutex twice and won't deadlock. Of course it also needs to unlock it twice, otherwise no other thread can obtain the mutex. Not all systems supporting pthreads also support recursive mutexes, but if they want to be P...
How can I get the full object in Node.js's console.log(), rather than '[Object]'?
...console.log(obj) it still prints [Object] for deeply nested objects :( I really wish it would behave as you describe.
– SSH This
Feb 23 '16 at 22:36
53
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How do I get the parent directory in Python?
...that does nothing but string manipulation. To verify if the pathname actually exist requires a disk access. Depends on the application this may or may not be desirable.
– Wai Yip Tung
May 18 '10 at 19:45
...
“unpacking” a tuple to call a matching function pointer
...S> struct gens<0, S...>{ typedef seq<S...> type; };
double foo(int x, float y, double z)
{
return x + y + z;
}
template <typename ...Args>
struct save_it_for_later
{
std::tuple<Args...> params;
double (*func)(Args...);
double delayed_dispatch()
{
return ca...