scope

问题 Hi guys I'm tring to create a scope which find out all contacts with 0 address. Got error message ArgumentError: tried to create Proc object without a block when running command 'Contact.noaddress' in rails c. here's my contact model including scope class Contact < ActiveRecord::Base attr_accessible :email, :firstname, :lastname, :mobilephone, :fullname has_many :addresses validates_presence_of :firstname, :lastname scope :noaddressed, lambda do |addresses| joins(:addresses).where('addresses

问题 I have a solution I'm trying to get to build on TFS. I want to update the versions of all appropriate files, and I've been stuck trying to get this done. There are plenty of links on how to do it, but none of them work for me, due to one little issue... Scope. <?xml version="1.0" encoding="utf-8"?> <Project DefaultTargets="DesktopBuild" xmlns="http://schemas.microsoft.com/developer/msbuild/2003" ToolsVersion="3.5"> <Target Name="DesktopBuild"> <CallTarget Targets="GetFiles" /> <Message Text=

问题 This question already has answers here : Explain the encapsulated anonymous function syntax (10 answers) Closed 5 years ago . I get confused when I see examples of self invoked anonymous functions in Javascript such as this: (function () { return val;}) (); Is there a difference between this syntax and the following: function() { return val;} (); If someone can give me a concrete difference, it would help put to rest a question that's been bugging me for ages... 回答1: Javascript doesn't have a

问题 The var keyword in javascript causes a variable to be stored in the local scope. Without var variables belong to the global scope. What about functions? It's clear what happens when functions are declared like variables var foo = function() {...} but what scope does function foo() {...} belong to? EDIT: I realized I didn't ask quite the right question so as a follow up. In the outer most nesting is there a difference between the above two declarations and the following declaration? foo =

问题 Every once in a while, I stumble across some code that I'm maintaining that challenges the way I think about my code style. Today was one of those days... I'm aware that about why you would want to use the scope operator to define global scope. In fact, here scope resolution operator without a scope is a great link tell you why. However, I saw something that made me think today. All the classes in question were wrapped into a namespace for the project (good!), but I did see copious usage of

问题 I am looking for some guidance on the difference between a global scope variable and a local scope variable. Thanks. 回答1: Global variable - declared at the start of the program, their global scope means they can be used in any procedure or subroutine in the program. Local variable - declared within subroutines or programming blocks, their local scope means they can only be used within the subroutine or program block they were declared in. Resource: Fundamentals of Programming: Global and

问题 I am reading this article about decorator. At Step 8 , there is a function defined as: def outer(): x = 1 def inner(): print x # 1 return inner and if we run it by: >>> foo = outer() >>> foo.func_closure # doctest: +ELLIPSIS it doesn't print x. According to the explanation : Everything works according to Python’s scoping rules - x is a local variable in our function outer. When inner prints x at point #1 Python looks for a local variable to inner and not finding it looks in the enclosing

问题 I'm trying to parallelize (using snow::parLapply ) some code that depends on a package (ie, a package other than snow ). Objects referenced in the function called by parLapply must be explicitly passed to the cluster using clusterExport . Is there any way to pass an entire package to the cluster rather than having to explicitly name every function (including a package's internal functions called by user functions!) in clusterExport ? 回答1: Install the package on all nodes, and have your code

问题 In the following code, can the x member be accessed from the nested object literal? var outer = { x : 0, inner: { a : x + 1, // 'x' is undefined. b : outer.x + 1, // 'outer' is undefined. c : this.x + 1 // This doesn't produce an error, } // but outer.inner.c is NaN. } 回答1: In the way you put it - no. You need two stages construction, this will work: var outer = { x : 0 }; // outer is constructed at this point. outer.inner = { b : outer.x + 1 // 'outer' is defined here. }; 回答2: Not in the

问题 I have a simple table with three rows and two values for each row - date and state: <tbody> <tr> <td>Red</td> <td class="lastModified">{{item.redDate}}</td> <td class="status"> <select id ="red" class="form-control" ng-change="update();" ng-model="item.redStatus"> <option value="" disabled="" selected="" class="ng-binding">Please select the value</option> <option ng-selected="step.value === item.redStatus" ng-repeat="(key, step) in steps">{{ step.title }}</option> </select> </td> </tr> <tr