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Difference between is and as keyword
Please tell what is the difference between is and as keyword in C#
14 Answers
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What part of Hindley-Milner do you not understand?
...must be true in order to guarantee the [below].
: means has type
∈ means is in. (Likewise ∉ means "is not in".)
Γ is usually used to refer to an environment or context; in this case it can be thought of as a set of type annotations, pairing an identifier with its type. Therefore x : σ ∈ Γ ...
How do I check if a string is a number (float)?
What is the best possible way to check if a string can be represented as a number in Python?
33 Answers
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JavaScript closures vs. anonymous functions
A friend of mine and I are currently discussing what is a closure in JS and what isn't. We just want to make sure we really understand it correctly.
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Is there any difference between “foo is None” and “foo == None”?
Is there any difference between:
12 Answers
12
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Why is null an object and what's the difference between null and undefined?
Why is null considered an object in JavaScript?
21 Answers
21
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is_null($x) vs $x === null in PHP [duplicate]
PHP has two (that I know of, and three if you count isset() ) methods to determine if a value is null: is_null() and === null . I have heard, but not confirmed, that === null is faster, but in a code review someone strongly suggested that I use is_null() instead as it is specifically design...
Type Checking: typeof, GetType, or is?
...ou specify at compile time).
GetType gets the runtime type of an instance.
is returns true if an instance is in the inheritance tree.
Example
class Animal { }
class Dog : Animal { }
void PrintTypes(Animal a) {
Console.WriteLine(a.GetType() == typeof(Animal)); // false
Console.WriteLin...
What is the difference between “instantiated” and “initialized”?
... been hearing these two words used in Microsoft tutorials for VB.NET. What is the difference between these two words when used in reference to variables?
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What is this operator in MySQL?
...rator.
Like the regular = operator, two values are compared and the result is either 0 (not equal) or 1 (equal); in other words: 'a' <=> 'b' yields 0 and 'a' <=> 'a' yields 1.
Unlike the regular = operator, values of NULL don't have a special meaning and so it never yields NULL as a poss...