2023年3月21日 · The code in the question is pseudo-code; there, := represents assignment. For future visitors, though, the following might be more relevant: the next version of Python (3.8) will gain a new operator, :=, allowing assignment expressions (details, motivating examples, and discussion can be found in PEP 572, which was provisionally accepted in late June 2018).

The first meaning is as an assignment operator. This is all we’ve talked about so far. The second meaning isn’t an operator but rather a syntax token that signals named argument passing in a function call. Unlike the = operator it performs no action at runtime, it merely changes the way an expression is parsed.

2010年12月22日 · If your assignment operator needs a check for self-assignment, chances are there's a better implementation. Good implementations (like Copy-And-Swap) don't need that test (which puts the burden of checking for the rare case on every assignment). –

2012年2月6日 · An assignment operator shall be implemented by a non-static member function with exactly one parameter. Because a copy assignment operator operator= is implicitly declared for a class if not declared by the user (12.8), a base class assignment operator is always hidden by the copy assignment operator of the derived class.

An older assignment operator is <-and, for compatibility reasons, it still remains functional, but it should be ignored to ensure cleaner programming. (As pointed out by Spector, P. (2009). 'Data Manipulation with R' - Section 8.7., an exception is when using system.time, since = is then used to identify keywords) A misleading feature of the ...

In modern C, or even moderately ancient C, += is a compound assignment operator, and =+ is parsed as two separate tokens. = and +. Punctuation tokens are allowed to be adjacent. So if you write: x += y; it's equivalent to. x = x + y; except that x is only evaluated once (which can matter if it's a more complicated expression). If you write: x =+ y;

2013年10月30日 · A operator=(const A &a) { std::cout<<"This is assignment operator."; return *this; This obviously prints "This is assignment operator.", then return *this; statement sees the return type of A and creates a return value of type A doing the equivalent of A(*this); -> that calls the copy constructor, explaining this part of the output:

2015年4月16日 · |= is a bitwise-OR-assignment operator. It takes the current value of the LHS, bitwise-ors the RHS, and assigns the value back to the LHS (in a similar fashion to += does with addition). For example:

2010年8月26日 · It is well-known what the automatically-generated assignment operator will do - that's defined as part of the standard and a standards-compliant C++ compiler will always generate a correctly-behaving assignment operator (if it didn't, then it would not be a standards-compliant compiler).

2012年3月1日 · An assignment expression has the value of the left operand after the assignment. It's to allow things like this: a = b = c; (although there's some debate as to whether code like that is a good thing or not.) Incidentally, this behaviour is replicated in Java (and I would bet that it's the same in C# too).