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@property retain, assign, copy, nonatomic in Objective-C
...omeone give me an overview of the retain, assign, copy and any others I'm missing, that follow the @property directive? What are they doing and why would I want to use one over another?
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What is JSON and why would I use it?
..., but I still haven't got to the point where I really understand what JSON is, and why I'd use it.
16 Answers
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How to check for null in Twig?
What construct should I use to check whether a value is NULL in a Twig template?
8 Answers
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The difference between Classes, Objects, and Instances
What is a class, an object and an instance in Java?
16 Answers
16
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What are the differences between NP, NP-Complete and NP-Hard?
...emember a preliminary needed concept to understand those definitions.
Decision problem: A problem with a yes or no answer.
Now, let us define those complexity classes.
P
P is a complexity class that represents the set of all decision problems that can be solved in polynomial time.
That is, ...
Why does NULL = NULL evaluate to false in SQL server
... have nullParam=NULL in a where clause, it always evaluates to false. This is counterintuitive and has caused me many errors. I do understand the IS NULL and IS NOT NULL keywords are the correct way to do it. But why does SQL server behave this way?
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“is” operator behaves unexpectedly with integers
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Take a look at this:
>>> a = 256
>>> b = 256
>>> id(a)
9987148
>>> id(b)
9987148
>>> a = 257
>>> b = 257
>>> id(a)
11662816
>>> id(b)
11662828
Here's what I found in t...
What's the difference between using “let” and “var”?
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Scoping rules
Main difference is scoping rules. Variables declared by var keyword are scoped to the immediate function body (hence the function scope) while let variables are scoped to the immediate enclosing block denoted by { } (hence the block scope).
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For i = 0, why is (i += i++) equal to 0?
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This:
int i = 0;
i += i++
Can be seen as you doing (the following is a gross oversimplification):
int i = 0;
i = i + i; // i=0 because the ++ is a postfix operator and hasn't been executed
i + 1; // Note that you are discar...