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Xcode doesn't show the line that causes a crash
Every time my app crashes Xcode highlights the UIApicationMain() call in the main() function as the line that caused the crash. In some cases that used to be normal (segmentation fault for example) but the crash I am trying to deal with is a simple SIGABRT with detailed information logged in the con...
Function return value in PowerShell
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PowerShell has really wacky return semantics - at least when viewed from a more traditional programming perspective. There are two main ideas to wrap your head around:
All output is captured, and returned
The return keyword really just indi...
Using variables inside a bash heredoc
... the
lines in the here-document are not expanded. If word is unquoted, all
lines of the here-document are subjected to parameter expansion, command substitution, and arithmetic expansion. [...]
If you change your first example to use <<EOF instead of << "EOF" you'll find that i...
__proto__ VS. prototype in JavaScript
...x = x;
this.y = y;
}
var myPoint = new Point();
// the following are all true
myPoint.__proto__ == Point.prototype
myPoint.__proto__.__proto__ == Object.prototype
myPoint instanceof Point;
myPoint instanceof Object;
Here Point is a constructor function, it builds an object (data structure) p...
What does 'super' do in Python?
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What's the difference?
SomeBaseClass.__init__(self)
means to call SomeBaseClass's __init__. while
super(Child, self).__init__()
means to call a bound __init__ from the parent class that follows Child in the instance's Method Resolution Order (MRO).
If the instance is a subclass of ...
StringBuilder vs String concatenation in toString() in Java
...o builder?
At the point where you're concatenating in a loop - that's usually when the compiler can't substitute StringBuilder by itself.
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Django Rest Framework: Dynamically return subset of fields
...verride the serializer __init__ method and set the fields attribute dynamically, based on the query params. You can access the request object throughout the context, passed to the serializer.
Here is a copy&paste from Django Rest Framework documentation example on the matter:
from rest_framew...
Scala: List[Future] to Future[List] disregarding failed futures
...ures to a Future of List. I'm using Playframework, so ultimately, what I really want is a Future[Result] , but to make things simpler, let's just say Future[List[Int]] The normal way to do this would be to use Future.sequence(...) but there's a twist... The list I'm given usually has around 10-...
Best algorithm for detecting cycles in a directed graph [closed]
What is the most efficient algorithm for detecting all cycles within a directed graph?
14 Answers
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JavaScript Regular Expression Email Validation [duplicate]
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If you define your regular expression as a string then all backslashes need to be escaped, so instead of '\w' you should have '\\w'.
Alternatively, define it as a regular expression:
var pattern = /^\w+@[a-zA-Z_]+?\.[a-zA-Z]{2,3}$/;
BTW, please don't validate email address...