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Overriding superclass property with different type in Swift

... Swift does not allow you to change the class type of any variables or properties. Instead you can create an extra variable in the subclass that handles the new class type: class Chassis {} class RacingChassis : Chassis {} class Car { ...
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How to disable HTML button using JavaScript?

I’ve read that you can disable (make physically unclickable) an HTML button simply by appending disable to its tag, but not as an attribute, as follows: ...
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Unix's 'ls' sort by name

...t the FILEs (the current directory by default). Sort entries alpha‐betically if none of -cftuvSUX nor --sort is specified.: share | improve this answer | follow ...
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“is” operator behaves unexpectedly with integers

...3): The current implementation keeps an array of integer objects for all integers between -5 and 256, when you create an int in that range you actually just get back a reference to the existing object. So it should be possible to change the value of 1. I suspect the behaviour of Py...
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Rspec doesn't see my model Class. uninitialized constant error

... Your spec_helper file is missing some important commands. Specifically, it's not including config/environment and initializing rspec-rails. You can add the following lines to the start of your spec/spec_helper.rb file ENV["RAILS_ENV"] ||= 'test' require File.expand_path("../../config/envi...
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What does the Ellipsis object do?

While idly surfing the namespace I noticed an odd looking object called Ellipsis , it does not seem to be or do anything special, but it's a globally available builtin. ...
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How to print to stderr in Python?

...to make your code Python3-ready. I guess this could be why many people actually like it! – MarcH Nov 18 '14 at 19:00 18 ...
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How to use Elasticsearch with MongoDB?

... instance. Make sure everything is up to date. sudo apt-get update Install NodeJS. sudo apt-get install nodejs sudo apt-get install npm Install MongoDB - These steps are straight from MongoDB docs. Choose whatever version you're comfortable with. I'm sticking with v2.4.9 because it seems to b...
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Is there a way to detach matplotlib plots so that the computation can continue?

... Use matplotlib's calls that won't block: Using draw(): from matplotlib.pyplot import plot, draw, show plot([1,2,3]) draw() print('continue computation') # at the end call show to ensure window won't close. show() Using interactive mode: from...
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How do I best silence a warning about unused variables?

I have a cross platform application and in a few of my functions not all the values passed to functions are utilised. Hence I get a warning from GCC telling me that there are unused variables. ...