In the following program, if I set the variable $foo to the value 1 inside the first if statement, it works in the sense that its value is remembered after the if statement. However, when I set the same variable to the value 2 inside an if which is inside a while statement, it’s forgotten … Read more
The following code works as expected in both Python 2.5 and 3.0: a, b, c = (1, 2, 3) print(a, b, c) def test(): print(a) print(b) print(c) # (A) #c+=1 # (B) test() However, when I uncomment line (B), I get an UnboundLocalError: ‘c’ not assigned at line (A). The values of a and b … Read more
This question already has answers here: Using global variables in a function (24 answers) Closed 3 years ago. Is there a way to set up a global variable inside of a module? When I tried to do it the most obvious way as appears below, the Python interpreter said the variable __DBNAME__ did not exist. … Read more
Is the underscore prefix in JavaScript only a convention, like for example in Python private class methods are? From the 2.7 Python documentation: “Private” instance variables that cannot be accessed except from inside an object don’t exist in Python. However, there is a convention that is followed by most Python code: a name prefixed with … Read more
Is it possible to declare two variables of different types in the initialization body of a for loop in C++? For example: for(int i=0,j=0 … defines two integers. Can I define an int and a char in the initialization body? How would this be done? 8 Answers 8
There is a lot of code in one of our projects that looks like this: internal static class Extensions { public static string AddFoo(this string s) { if (s == null) { return “Foo”; } return $({s}Foo); } } Is there any explicit reason to do this other than “it is easier to make the … Read more
This question already has answers here: UnboundLocalError on local variable when reassigned after first use (12 answers) Closed 6 years ago. The following code gives the error UnboundLocalError: local variable ‘Var1’ referenced before assignment: Var1 = 1 Var2 = 0 def function(): if Var2 == 0 and Var1 > 0: print(“Result One”) elif Var2 == … Read more
I’m new to Python, so this is probably a simple scoping question. The following code in a Python file (module) is confusing me slightly: if __name__ == ‘__main__’: x = 1 print x In other languages I’ve worked in, this code would throw an exception, as the x variable is local to the if statement … Read more
I saw the following in the source for WebKit HTML 5 SQL Storage Notes Demo: function Note() { var self = this; var note = document.createElement(‘div’); note.className=”note”; note.addEventListener(‘mousedown’, function(e) { return self.onMouseDown(e) }, false); note.addEventListener(‘click’, function() { return self.onNoteClick() }, false); this.note = note; // … } The author uses self in some places (the … Read more
I noticed that there are different bean scopes like: @RequestScoped @ViewScoped @FlowScoped @SessionScoped @ApplicationScoped What is the purpose of each? How do I choose a proper scope for my bean? 2 Answers 2
