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Function in JavaScript that can be called only once
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If by "won't be executed" you mean "will do nothing when called more than once", you can create a closure:
var something = (function() {
var executed = false;
return function() {
if (!executed) {
executed = true;
// do something
}
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Are there any JavaScript static analysis tools? [closed]
... Dec 14 '11 at 4:54
Andrew Marshall
87.3k1818 gold badges202202 silver badges204204 bronze badges
answered Apr 2 '09 at 17:46
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How to change the background color of the options menu?
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After spending a considerable amount of time trying all the options, the only way I was able to get an app using AppCompat v7 to change the overflow menu background was using the itemBackground attribute:
<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar"&...
How can you profile a Python script?
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Python includes a profiler called cProfile. It not only gives the total running time, but also times each function separately, and tells you how many times each function was called, making it easy to determine where you should make optimizations.
You c...
Adding :default => true to boolean in existing Rails column
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change_column is a method of ActiveRecord::Migration, so you can't call it like that in the console.
If you want to add a default value for this column, create a new migration:
rails g migration add_default_value_to_show_attribute
Then in the migration created:
# That's the more generic way t...
Is it possible to clone html element objects in JavaScript / JQuery?
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Too bad you lose all attributes :/
– Pieter De Bie
Sep 23 '19 at 12:49
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KIO4_Gradient 拓展：布局中的颜色渐变 - App Inventor 2 中文网 - 清泛IT...
http://kio4.com/appinventor/287_extension_gradiente_color.htm
- 让我们看一下在布局中制作颜色渐变的扩展。- 我们放置一个布局，然后在该扩展的块中插入该布局的名称，放置一个包含所需颜色的列表，以及一个从 1 到 8 的数字，用于表示...
Build Eclipse Java Project from Command Line
...ore.aptBuild
It uses the jdt apt plugin to build your workspace automatically. This is also known as a 'Headless Build'. Damn hard to figure out. If you're not using a win32 exe, you can try this:
java -cp startup.jar -noSplash -data "D:\Source\MyProject\workspace" -application org.eclipse.jdt....
TypeLoadException says 'no implementation', but it is implemented
...nt - for me 'running again' implied F5. I've updated the answer. Of course all this wouldn't have happened with a decent source control tool, but don't get me started on that subject...
– Benjol
Jun 4 '09 at 6:21
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理解Python的 with 语句 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...hat the statement after with has to evaluate an object that responds to an __enter__() as well as an __exit__() function.
这看起来充满魔法，但不仅仅是魔法，Python对with的处理还很聪明。基本思想是with所求值的对象必须有一个__enter__()方法，一个__exit__()...