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Why is Scala's immutable Set not covariant in its type?
...ameter of type A due to the contravariance of functions. Set could potentially be contravariant in A, but this too causes issues when you want to do things like this:
def elements: Iterable[A]
In short, the best solution is to keep things invariant, even for the immutable data structure. You'll...
Convert stdClass object to array in PHP
...ncode($object), true);
Or if you prefer, you can traverse the object manually, too:
foreach ($object as $value)
$array[] = $value->post_id;
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When should I use ugettext_lazy?
I have a question about using ugettext and ugettext_lazy for translations.
I learned that in models I should use ugettext_lazy , while in views ugettext.
But are there any other places, where I should use ugettext_lazy too? What about form definitions?
Are there any performance diffrences betwe...
Checkbox for nullable boolean
...iad of different reasons why the foo input might not appear on the page at all. If it does appear I can assume there's a value, but I need to be able to differentiate between when the model is posted with foo as unchecked and when foo isn't shown.
– DMulligan
J...
Set Focus on EditText
... set an OnFocusChangeListener for it. When it has lost focus, a method is called, which checks the value of the EditText with one in the database. If the return-value of the method is true, a toast is shown and the focus should get back on the EditText again. The focus should always get back on the ...
AngularJS For Loop with Numbers & Ranges
... You have to watch out for things like this. The range function will get called multiple times for each item in the list. You can get nasty memory leaks and you're generating a lot of function calls. It almost seems easier to put the collection inside the controller.
– Lucas ...
Regex, every non-alphanumeric character except white space or colon
...
[^a-zA-Z\d\s:]
\d - numeric class
\s - whitespace
a-zA-Z - matches all the letters
^ - negates them all - so you get - non numeric chars, non spaces and non colons
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How to close current tab in a browser window?
...ndow.close();
or you can specify a different window.
So:
function close_window() {
if (confirm("Close Window?")) {
close();
}
}
with HTML:
<a href="javascript:close_window();">close</a>
or:
<a href="#" onclick="close_window();return false;">close</a>
You r...
Zero-based month numbering [closed]
...
The use of zero to start counting is actually an optimization trick from Assembly programmers. Instead of assigning 1 to the count register, they XOR'ed the register with itself, which was slightly faster in CPU cycles. This meant that counting would start with 0 an...
Are Swift variables atomic?
... you, i.e.:
class Car {
static let sharedCar: Car = Car() // will be called inside of dispatch_once
}
private let sharedCar: Car2 = Car2() // same here
class Car2 {
}
Update 05/25/16: Keep an eye out for swift evolution proposal https://github.com/apple/swift-evolution/blob/master/proposals...