methods

问题 I try to override this method def sum[B >: A](implicit num: Numeric[B]): B = ... in a subclass where type A is already fixed to Int . I already tried override def sum: Int = ... but this doesn't override of course, leading to different method resolution based on the dynamic type at runtime. Going further, def sum[B >: Int](implicit num: Numeric[B]): Int does override, while def sum[B >: Int](implicit num: Numeric[Int]): Int does not, as well as def sum(implicit num: Numeric[Int]): Int Why is

问题 I have something that should be really simple, but it's killing me. l = LineItem.first #<LineItem id: 5, product_id: 1, quantity: 1, price: #<BigDecimal:7f7fdb51a3f8,'0.999E3',9(18)>, cart_id: 5, discount_percentage: 10, discount_amount: nil, discount_active: true, created_at: "2012-01-12 16:17:41", updated_at: "2012-01-12 16:17:41"> I have l.discount_percentage.blank? => false So, I have the following method: def total_price discount_amount = 0 if discount_amount.blank? discount_percentage =

问题 I have yet another issue which the answer is eluding me. I wish to take a class from an external jar at runtime and grab a method from it and pass it a parameter. My code below currently opens the jar and grabs the class and runs the method but when I try and pass it a parameter, the method runs but I get an InvocationTargetException. Any ideas? Here is my code: String path = "test.jar"; URL[] classes = {new File(path).toURI().toURL()}; URLClassLoader child = new URLClassLoader (classes, this

问题 My method to delete an image from database and local storage. public function destroy($id) { $image = DB::table('images')->where('id', '=', $id)->first(); //print_r($image); //return 'end'; File::delete(public_path() . '/images/gallery/thumb-' . $image->path); File::delete(public_path() . '/images/gallery/' . $image->path); $image->delete(); return Redirect::back() ->with('form_success', 1) ->with('form_message', 'Image successfully deleted!'); } If I try to return value of $image I get:

问题 I think it would be natural to have in Ruby something like: class Object def yield_self yield(self) end end Does there exist a method like this by any chance? (I haven't found.) Does anybody else think it would be nice to have it? 回答1: yield_self has been added to ruby core a month ago as of June 2017. https://bugs.ruby-lang.org/projects/ruby-trunk/repository/revisions/58528 It's in ruby 2.5.0 after revision number 58528, although I'm not exactly sure how to get that code yet. Perhaps if

问题 I see when I look at an order it will show the specific item that was refunded if the whole order wasn't. Is there a way to find using the WC_Order_Item_Product if an item was refunded? Also, is there a way to get the discount amount that shows up below the item in the order view? I'm currently doing it manually but if there is a function for it already, I would rather use it. 回答1: To get the order refunds you you use some dedicated WC_Order methods like the following ones that have the Item

问题 This is my methods.phtml file in onepagecheckout in magento,I want the dropdown(select option) button instead of radio button .........so that i could select the payment method to pay the payment. <?php if (!$methods = $this->getMethods()) : ?> <p><?php echo $this->helper('checkout')->__('Sorry, no quotes are available for this order at this time.') ?></p> <?php else : ?> <dl class="sp-methods"> <?php foreach ($this->getMethods() as $_method): $_code = $_method->getCode() ?> <dt> <?php if(

问题 I have the following code: import numpy as np class ClassProperty(property): def __get__(self, cls, owner): return self.fget.__get__(None, owner)() def coord(cls, c): if cls.dimension <= 2: return c else: return c + [0]*(cls.dimension-2) class Basis_NonI(object): @ClassProperty @classmethod def zerocoord(cls): return coord(cls, [0,0]) def __init__(self, dimension): pass class Basis_D(Basis_NonI): dimension = 2 proj_matrix = np.array([Basis_D.zerocoord, Basis_D.zerocoord]) def __init__(self,

问题 My question is somewhat similar to this one; it concerns object methods rather than module contents. I want to know if I can use the inspect module to get the methods defined only in the class I'm asking about , and not its parent(s). I need this because my child class defines 'macro' methods, which accesses the parent's methods at a higher level of abstraction, and I don't want the user to have to worry about the lower-level methods defined all the way up the inheritance tree. Here is a

问题 I've asked my teacher this a thousand times and he explained it to me just as many times, but I still don't get when to use static in variables/methods Could someone give a metaphorical explanation for this, maybe also showing some examples where static is needed and where not? 回答1: Do I want to access the method without an instance of the class? If you answered yes, you probably want a static method. private static variables can be used to share data across instances of that class, i.e. if