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How to overload functions in javascript?
...by checking the type, presence or quantity of arguments.
jQuery does this all the time. You can make some of the arguments optional or you can branch in your function depending upon what arguments are passed to it.
In implementing these types of overloads, you have several different techniques yo...
instantiate a class from a variable in PHP?
...eck them out here (call_user_func_array , call_user_func).
example
class Foo {
static public function test() {
print "Hello world!\n";
}
}
call_user_func('Foo::test');//FOO is the class, test is the method both separated by ::
//or
call_user_func(array('Foo', 'test'));//alternatively you c...
How to make rounded percentages add up to 100%
...55310199789695, 8.780231335436383, 8.04416403785489, 0]. The last one logically returns -1. I thought of the following solution really quickly but there's probably something better: jsfiddle.net/0o75bw43/1
– Cruclax
Aug 5 '16 at 16:39
...
What is the difference between Python's list methods append and extend?
...
Actually there's a big difference - x + [4, 5] gives you a new list assigned to x - x.extend() mutates the original list. I elaborate in my answer here below.
– Aaron Hall♦
Jul 17 '17 at 1...
Creating a singleton in Python
...mple implementation:
class Singleton(type):
_instances = {}
def __call__(cls, *args, **kwargs):
if cls not in cls._instances:
cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
return cls._instances[cls]
class Logger(object):
__meta...
What is the difference between a definition and a declaration?
...// extern can be omitted for function declarations
class foo; // no extern allowed for type declarations
A definition actually instantiates/implements this identifier. It's what the linker needs in order to link references to those entities. These are definitions corresponding to the above declara...
super() raises “TypeError: must be type, not classobj” for new-style class
...pe(OldStyle()) is the instance type, which does inherit from object. Basically, an old-style class just creates objects of type instance (whereas a new-style class creates objects whose type is the class itself). This is probably why the instance OldStyle() is an object: its type() inherits from ob...
New self vs. new static
...uated at compile time and must not depend on run-time information.
class Foo {
public $name = static::class;
}
$Foo = new Foo;
echo $Foo->name; // Fatal error
Using self::
class Foo {
public $name = self::class;
}
$Foo = new Foo;
echo $Foo->name; // Foo
Please note that ...
Adding 'serial' to existing column in Postgres
I have a small table (~30 rows) in my Postgres 9.0 database with an integer ID field (the primary key) which currently contains unique sequential integers starting at 1, but which was not created using the 'serial' keyword.
...
How to get POSTed JSON in Flask?
...
First of all, the .json attribute is a property that delegates to the request.get_json() method, which documents why you see None here.
You need to set the request content type to application/json for the .json property and .get_jso...