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Why do some functions have underscores “__” before and after the function name?
...sing leading or trailing underscores are
recognized (these can generally be combined with any case convention):
_single_leading_underscore: weak "internal use" indicator. E.g. from M import * does not import objects whose name starts with an underscore.
single_trailing_underscore_: used ...
Difference between a theta join, equijoin and natural join
I'm having trouble understanding relational algebra when it comes to theta joins, equijoins and natural joins. Could someone please help me better understand it? If I use the = sign on a theta join is it exactly the same as just using a natural join?
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Custom views with Storyboard
...whole thing in smaller pieces (I call them widgets). These widgets consist basically of a MyWidget.h and a MyWidget.m file as well as a MyWidget.xib file, where the root element is a UIView and the MyWidget class is the File Owner of the UIView. In the init of this widget I do a loadNibName...
Why use HttpClient for Synchronous Connection
I am building a class library to interact with an API. I need to call the API and process the XML response. I can see the benefits of using HttpClient for Asynchronous connectivity, but what I am doing is purely synchronous, so I cannot see any significant benefit over using HttpWebRequest .
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Create a tar.xz in one command
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Use the -J compression option for xz. And remember to man tar :)
tar cfJ <archive.tar.xz> <files>
Edit 2015-08-10:
If you're passing the arguments to tar with dashes (ex: tar -cf as opposed to tar cf), then the -f option must come last, since it specifies ...
HashSet vs. List performance
...is higher than of the generic List<T> class. Just compare the hash-based key with the linear approach in the List<T> class.
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When should I use the Visitor Design Pattern? [closed]
I keep seeing references to the visitor pattern in blogs but I've got to admit, I just don't get it. I read the wikipedia article for the pattern and I understand its mechanics but I'm still confused as to when I'd use it.
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What is the equivalent of the C# 'var' keyword in Java?
... none. Alas, you have to type out the full type name.
Edit: 7 years after being posted, type inference for local variables (with var) was added in Java 10.
Edit: 6 years after being posted, to collect some of the comments from below:
The reason C# has the var keyword is because it's possible t...
How can I style an Android Switch?
The switch widget introduced in API 14 is styled by default with holo theme.
I want to style it slightly different, changing its colors and shape a bit for branding reasons. How does one go about this? I know it must be possible, as ive seen the difference between default ICS and Samsung's touchwiz ...
Mark error in form using Bootstrap
I've started using Bootstrap in order to achieve a nice page design without resorting to GWT (the backend is made in java)
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