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How can I determine if a variable is 'undefined' or 'null'?
...enceError and break execution if variable is not defined or referred to at all in the code, using typeof is safer.
– Mani Gandham
Jun 15 '14 at 9:49
59
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How do I handle too long index names in a Ruby on Rails ActiveRecord migration?
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Provide the :name option to add_index, e.g.:
add_index :studies,
["user_id", "university_id", "subject_name_id", "subject_type_id"],
:unique => true,
:name => 'my_index'
If using the :index option on references in a create_table block, it t...
void in C# generics?
...nctions need to return null, but if it unifies your code, it should be a small price to pay.
This inability to use void as a return type is at least partially responsible for a split between the Func<...> and Action<...> families of generic delegates: had it been possible to return void...
Most efficient way to reverse a numpy array
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When you create reversed_arr you are creating a view into the original array. You can then change the original array, and the view will update to reflect the changes.
Are you re-creating the view more often than you need to? You should be able to...
Using Rails 3.1, where do you put your “page specific” JavaScript code?
To my understanding, all of your JavaScript gets merged into 1 file. Rails does this by default when it adds //= require_tree . to the bottom of your application.js manifest file.
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Secure random token in Node.js
...oding in node is not url-safe, it includes / and + instead of - and _ . Therefore, the easiest way to generate such token I've found is
...
HTML5 Canvas 100% Width Height of Viewport?
....getContext('2d');
// resize the canvas to fill browser window dynamically
window.addEventListener('resize', resizeCanvas, false);
function resizeCanvas() {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
/**
* You...
How to copy a selection to the OS X clipboard
...xists only for X11 (unless you build vim with +X11 support, which will install a X11 server XQuartz in OS X), while OS X doesn't use X11 as its windows system.
– nn0p
Nov 27 '16 at 18:20
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How to strip all non-alphabetic characters from string in SQL Server?
How could you remove all characters that are not alphabetic from a string?
18 Answers
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How do you prevent IDisposable from spreading to all your classes?
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You can't really "prevent" IDisposable from spreading. Some classes need to be disposed, like AutoResetEvent, and the most efficient way is to do it in the Dispose() method to avoid the overhead of finalizers. But this method must be cal...