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What does “error: option --single-version-externally-managed not recognized” indicate?
...not recognized when pip install ing varions packages (including PyObjC and astropy ). I've never seen this error before, but it's now also showing up on travis-ci builds for which nothing has changed.
...
How to properly create composite primary keys - MYSQL
... gross oversimplification of an intense setup I am working with. table_1 and table_2 both have auto-increment surrogate primary keys as the ID. info is a table that contains information about both table_1 and table_2 .
...
Rails extending ActiveRecord::Base
...
Create a file in the config/initializers directory called extensions.rb and add the following line to the file:
require "active_record_extension"
Inheritance (Preferred)
Refer to Toby's answer.
Monkey patching (Should be avoided)
Create a file in the config/initializers directory called act...
How to use JavaScript regex over multiple lines?
...to match all newlines, you would need to add \r as well to include Windows and classic Mac OS style line endings: (.|[\r\n]).
That turns out to be somewhat cumbersome, as well as slow, (see KrisWebDev's answer for details), so a better approach would be to match all whitespace characters and all no...
How does this CSS produce a circle?
...f 180 pixels?
Let's reformulate that into two questions:
Where do width and height actually apply?
Let's have a look at the areas of a typical box (source):
The height and width apply only on content, if the correct box model is being used (no quirks mode, no old Internet Explorer).
Where d...
What does “=>” mean in PHP?
...the context of that foreach loop, it assigns the key of the array to $user and the value to $pass.
Example:
$user_list = array(
'dave' => 'apassword',
'steve' => 'secr3t'
);
foreach ($user_list as $user => $pass) {
echo "{$user}'s pass is: {$pass}\n";
}
// Prints:
// "dave's...
What is the difference between Python's list methods append and extend?
What's the difference between the list methods append() and extend() ?
20 Answers
2...
What does the Reflect object do in JavaScript?
... http://people.mozilla.org/~jorendorff/es6-draft.html#sec-reflect-object and it sounds similar to the Proxy object apart from the realm and loader functionality.
...
How can I get Visual Studio 2008 Windows Forms designer to render a Form that implements an abstract
I engaged a problem with inherited Controls in Windows Forms and need some advice on it.
10 Answers
...
Calculating frames per second in a game
...asiest way is to take the current answer (the time to draw the last frame) and combine it with the previous answer.
// eg.
float smoothing = 0.9; // larger=more smoothing
measurement = (measurement * smoothing) + (current * (1.0-smoothing))
By adjusting the 0.9 / 0.1 ratio you can change the 'tim...