When Python attempts to multiply two objects, it first tries to call the left object’s __mul__() method. If the left object doesn’t have a __mul__() method (or the method returns NotImplemented, indicating it doesn’t work with the right operand in question), then Python wants to know if the right object can do the multiplication. If … Read more
It means not equal to. It was taken from ABC (python’s predecessor) see here: x < y, x <= y, x >= y, x > y, x = y, x <> y, 0 <= d < 10 Order tests (<> means ‘not equals’) I believe ABC took it from Pascal, a language Guido began programming … Read more
If you do not define these four methods (six in C++11) the compiler will generate them for you: Default Constructor Copy Constructor Assignment Operator Destructor Move Constructor (C++11) Move Assignment (C++11) If you want to know why? It is to maintain backward compatibility with C (because C structs are copyable using = and in declaration). … Read more
Rule of thumb: Use -a and -o inside square brackets, && and || outside. It’s important to understand the difference between shell syntax and the syntax of the [ command. && and || are shell operators. They are used to combine the results of two commands. Because they are shell syntax, they have special syntactical … Read more
There are three options: >>> 4 / float(100) 0.04 >>> 4 / 100.0 0.04 which is the same behavior as the C, C++, Java etc, or >>> from __future__ import division >>> 4 / 100 0.04 You can also activate this behavior by passing the argument -Qnew to the Python interpreter: $ python -Qnew >>> … Read more
This is the same as ^ in most languages, just an XOR. false ^ false == false true ^ false == true false ^ true == true true ^ true == false
That’s heredoc syntax. You start a heredoc string by putting <<< plus a token of your choice, and terminate it by putting only the token (and nothing else!) on a new line. As a convenience, there is one exception: you are allowed to add a single semicolon after the end delimiter. Example: echo <<<HEREDOC This … Read more
I know this is a rather old post but I wanted simplify the answer since I stumbled upon it while looking for something else. XOR (eXclusive OR/either or), can be translated simply as toggle on/off. Which will either exclude (if exists) or include (if nonexistent) the specified bits. Using 4 bits (1111) we get 16 … Read more
**: exponentiation ^: exclusive-or (bitwise) %: modulus //: divide with integral result (discard remainder)
An example from msdn public struct Complex { double re, im; public override bool Equals(Object obj) { return obj is Complex c && this == c; } public override int GetHashCode() { return re.GetHashCode() ^ im.GetHashCode(); } public static bool operator ==(Complex x, Complex y) { return x.re == y.re && x.im == y.im; } … Read more