2020 answer: Since Python 3.8, the “walrus operator” := exists that does exactly what you want: while data := fgetcsv(fh, 1000, “,”) != False: pass (if that fgetcsv function existed) 2013 answer: You can’t do that in Python, no assignment in expressions. At least that means you won’t accidentally type == instead of = or … Read more
Yes. There are two common options. One – which is generally discouraged – is to call the operator= from the copy constructor explicitly: MyClass(const MyClass& other) { operator=(other); } However, providing a good operator= is a challenge when it comes to dealing with the old state and issues arising from self assignment. Also, all members … Read more
Yes. There are two common options. One – which is generally discouraged – is to call the operator= from the copy constructor explicitly: MyClass(const MyClass& other) { operator=(other); } However, providing a good operator= is a challenge when it comes to dealing with the old state and issues arising from self assignment. Also, all members … Read more
What you’re experiencing is commonly known as “variable shadowing”. When you use := with any variable in an inner scope, including in statements like if and for despite the lack of braces, a new value and type are associated with that variable: n := “Example” //Prints the string variable `n` to standard output and // … Read more
There are two distinct dot syntaxes being used here. They look the same, but they do different things depending on what they are operating on and what is being done with it: The first myView.frame is a shorthand for [myView frame], a method call that returns a CGRect struct by value. myFrame.origin.x is accessing ordinary … Read more
Yes: float[] values = {0.1f, 0.2f, 0.3f}; This syntax is only permissible in an initializer. You cannot use it in an assignment, where the following is the best you can do: values = new float[3]; or values = new float[] {0.1f, 0.2f, 0.3f}; Trying to find a reference in the language spec for this, but … Read more
I think the answer depends on the compiler. The language specifies: At run-time, the result of the assignment expression is the value of the variable after the assignment has occurred. I suppose that theoretically the value could be changed before the second (leftmost) assignment occurs. However, with Sun’s javac compiler, method1 will will turn into: … Read more
As you’ve now mentioned casting… there is a difference in this case: byte a = 5; a += 10; // Valid a = a + 10; // Invalid, as the expression “a + 10” is of type int From the Java Language Specification section 15.26.2: A compound assignment expression of the form E1 op= E2 … Read more
The first one is not legal in C#. The only two items that can appear after the colon in a constructor are base and this. So I’d go with the second one.
This is how you need to write it: scala> def prod(m: Int) = { | for { | a <- 2 to m / (2 * 3) | _ = print(a + ” “) | b <- (a + 1) to (m / a) | c = a * b | if c < m … Read more