instance-variables

Ran into some weird behaviour and wondering if anyone else can confirm what I am seeing. Suppose you create a class with a member variable, and allow it to be read with attr_reader. class TestClass attr_reader :val def initialize(value) @val = value end end Now when I do the following, it seems to modify the value of @val, even though I have only granted it read privileges. test = TestClass.new('hello') puts test.val test.val << ' world' puts test.val This returns hello hello world This is just the result from some testing I did in irb so not sure if this is always the case You are not really

This is a conceptual question and I haven't been able to find the answer in SO, so here I go: Why instance variables are used to connect controllers and views? Don't we have two different objects of two different classes (Controller vs Views). So, when the view is rendered we are in a different context, but we are using instance variables of another object? Isn't this breaking encapsulation in somehow? How does Rails manage to do that matching from one object to another? Does it clone all the instances variables of the controller to the view? In a sense, you could say that it is breaking

Consider the code below: <?php class Base { protected $name = "Base"; public function getName() { return $this->name; } } class Foo extends Base { protected $name = "Foo"; } $f = new Foo(); echo $f->getName(); // output: Foo $b = new Base(); echo $b->getName(); // output: Base Since in other languages such as Java won't allow you to override the instance variable, but it is possible in PHP. Is it because since PHP is weak type language so it is possible? No, it has nothing to do with weak typing . I guess this was simply a design decision that the PHP developers took. It may be because it is

I have just tried to lint some code with Pylint, and the last remaining error is R0902: too-many-instance-attributes (8/7) I understand the rationale behind limiting the number of instance attributes, but seven seems a bit low. I also realise that the linter should not have the last word. However, I would like to know what I should be doing instead of: def __init__(self, output_file=None, output_dir=None): """ Set the frobnicator up, along with default geometries """ self.margin = 30 self.pos = [0, 0] self.sep = [5, 5] self.cell = [20, 20] self.frobbr = library.Frobbr() page = self.frobbr.get