init

问题 Consider the following code: typealias PersonRecord = [String : AnyObject] struct Person { let name: String let age: Int public init(name: String, age: Int) { self.name = name self.age = age } } extension Person { init?(record : PersonRecord) { guard let name = record["name"] as? String, let age = record["age"] as? Int else { return nil } self.name = name self.age = age } } Now I want to create an array of Person s from an array of Record s: let records = // load file from bundle let persons

问题 I have read other questions which explain the difference between __init__ and __new__ but I just do not understand why in the following code with python 2 out: init and Python3: new init The sample code: class ExampleClass(): def __new__(cls): print ("new") return super().__new__(cls) def __init__(self): print ("init") example = ExampleClass() 回答1: To use __new__ in Python 2.x, the class should be new-style class (class derived from object ). And call to super() is different from that of

问题 When solving this problem I figured out that I need to disable the site-wise init files in order to get my emacs + CEDET running (everything works nicely when starting emacs using emacs --no-site-file but is broken without the additional argument). I'd like to disable the site-wise init files permanently but as I'm using several different approaches/methods when launching emacs (launcher/panel/terminal) I don't think aliasing it in my .zshrc won't work. I require a method to permanently

问题 I want to create a subclass of UINavigationController which always starts with the same root controller. Nothing special, so (to me) it makes perfect sense to override the init method like this: - (id) init { rootController = [[MyController alloc] init]; if (self = [super initWithRootViewController:rootController]) { // do some more initialization } return self; } This obviously creates a problem, because [super initWithRootViewController] will call [UINavigationController init], which is of

问题 So I'm calling this in a method: -(id)initWithContentURL:(NSString *)url { if (self = [super init]) { NSLog(@"xSheetMusicViewController - %@",url); // Casting an NSString object pointer to a CFStringRef: CFStringRef cfString = (CFStringRef)url; CFURLRef pdfURL = CFBundleCopyResourceURL(CFBundleGetMainBundle(), cfString, NULL, NULL); pdf = CGPDFDocumentCreateWithURL((CFURLRef)pdfURL); } return self; } Which crashes right at the NSLog at the line marked: CFURLRef pdfURL =

问题 i am trying to emulate cavium octeon's mips64 linux kernel on Qemu.I am currently having some issues with use mode init code and want to debug init.i am starting the Qemu using -s -S option in the command line and running the gdb using command ddd --debugger /OCTEON-SDK/tools/bin/mips64-octeon-linux-gnu-gdb /OCTEON-SDK/linux/kernel_2.6/linux/vmlinux and then attaching the gdb with command target remote localhost:1234 The gdb is currently showing only the instructions running in kernel space.

问题 I have this code: def __init__(self, a, b, c, d...): self.a = a self.b = b etc I'm thinking of replacing it with: def __init__(self, a, b, c, d...): args=locals() for key in args: self.__dict__[key] = args[key] Is this a bad idea? Are there any better ways to do this? 回答1: Building on @ThiefMaster's comment about **kwargs : If you are taking in 20 arguments, it might make more sense to require your users to send arguments via keyword instead of position: with 20 arguments, there is a decent

问题 I am having a hard time figuring out the purpose some code that I've come across. The code has a class Foo , which has an __init__ method that takes multiple arguments. From what I've learned of Python so far, by calling Foo('bar') , it will pass this string as a parameter to __init__ (which I think is supposed to be the equivalent of a constructor). But the issue I am having is that the code I am looking at is calling Foo.__init__('bar') directly. What is the purpose of this? I almost feel

问题 I've created a UIView subclass and corresponding xib file where I've laid out some UILabels and UIImageViews. I want to then put multiple copies of this custom UIView into a UIViewController. When I do that they appear blank in interface builder and don't appear when the app loads. What methods do I need to implement on the UIView subclass to make this work? 回答1: The easiest method by far is to create a nib with File's Owner set to NSObject, containing one view containing your layout element.

问题 I'm using Mac OS X with PyCharm and Python 3.5.1 and Blender 2.77. I'm using Blender with Python scripts. I understand that in order to run Python scripts that use Blender (i.e. that imports bpy ), I need to run it from command line using blender -b -P /path/to/my_python_script.py (although I don't really know why). That's all fine and it works, but I wish I could just run it from inside Python, because I use these scripts with other non-Blender Python code and I like to use PyCharm to debug