global-variables

问题 This snippet of code is from JuliaBoxTutorials myfriends = ["Ted", "Robyn", "Barney", "Lily", "Marshall"] i = 1; while i <= length(myfriends) friend = myfriends[i] println("Hi $friend, it's great to see you!") i += 1 end giving this error when run with Julia v1.0 UndefVarError: i not defined Stacktrace: [1] top-level scope at ./In[12]:5 [inlined] [2] top-level scope at ./none:0 But when i += 1 is replaced with global i += 1 it works. I guess this was still working in v0.6 and the tutorial

问题 This question already has an answer here : Closed 6 years ago . Possible Duplicate: Why is not the keyword global not required in this case? I wonder why I can change global dictionary without global keyword? Why it's mandatory for other types? Is there any logic behind this? E.g. code: #!/usr/bin/env python3 stringvar = "mod" dictvar = {'key1': 1, 'key2': 2} def foo(): dictvar['key1'] += 1 def bar(): stringvar = "bar" print(stringvar) print(dictvar) foo() print(dictvar) print(stringvar) bar(

问题 I want to define a constant that should be available in all of the submodules of a package. I've thought that the best place would be in in the __init__.py file of the root package. But I don't know how to do this. Suppose I have a few subpackages and each with several modules. How can I access that variable from these modules? Of course, if this is totally wrong, and there is a better alternative, I'd like to know it. 回答1: You should be able to put them in __init__.py . This is done all the

问题 I want to define a constant that should be available in all of the submodules of a package. I've thought that the best place would be in in the __init__.py file of the root package. But I don't know how to do this. Suppose I have a few subpackages and each with several modules. How can I access that variable from these modules? Of course, if this is totally wrong, and there is a better alternative, I'd like to know it. 回答1: You should be able to put them in __init__.py . This is done all the

问题 Suppose I have a global variable, and I want to assign another variable to it. I've found out that you can assign another value to a global variable inside a function: int i = 8; int main(void) { i = 9; /* Modifies i */ return 0; } However, assignment of the global variable outside of a function does not work! int i = 8; i = 9; /* Compiler error */ int main(void) { return 0; } I get the following error message: warning: data definition has no type or storage class warning: type defaults to

问题 Suppose I have a global variable, and I want to assign another variable to it. I've found out that you can assign another value to a global variable inside a function: int i = 8; int main(void) { i = 9; /* Modifies i */ return 0; } However, assignment of the global variable outside of a function does not work! int i = 8; i = 9; /* Compiler error */ int main(void) { return 0; } I get the following error message: warning: data definition has no type or storage class warning: type defaults to

问题 I used to put Global variables in environment.rb with my Rails 2.3.8 application such as: MAX_ALLOWD_ITEMS = 6 It doesn't seem to work in Rails 3. I tried putting it in application.rb and that didn't help. What do you suggest? 回答1: If you have already tried restarting your server as Ryan suggested, try putting it in your application.rb like this: module MyAppName class Application < Rails::Application YOUR_GLOBAL_VAR = "test" end end Then you can call it with the namespace in your controllers

问题 I'm new to angular and I'm wondering how I can share a variable between controllers in angular. I'm using the following scripts - In Main.js: function MainCntl($scope) { ---code } function SearchCtrl($scope, $http) { $scope.url = 'http://10.0.0.13:9000/processAdHoc'; $scope.errorM = "No results"; $scope.search = function() { $http.post($scope.url, { "data" : $scope.keywords}). success(function(data, status) { $scope.status = status; $scope.data = data; $scope.result = data; alert('yes'); }) .

问题 I just want to use a $variable at several places: not only views and controllers, but also in the routes.php and other configuration files. I don't want things like: use the Config class to load configuration files; use CI's get_instance , et cetera. I just want to declare a given $variable (it could be a constant, but I need it as a variable), and use it absolutely everywhere. In fact... I'd like to know which PHP file in the CI bootstrap is one of the first to be parsed, so I could

问题 What is the major difference between JavaScript declared and undeclared variables, since the delete operator doesn't work on declared variables? var y = 43; // declares a new variable x = 42; delete x; // returns true (x is a property of the global object and can be deleted) delete y; // returns false (delete doesn't affect variable names) Why does this happen? Variables declared globally are also the properties of the window object, so why can't it be deleted? 回答1: Declared and undeclared