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Explaining Python's '__enter__' and '__exit__'
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Using these magic methods (__enter__, __exit__) allows you to implement objects which can be used easily with the with statement.
The idea is that it makes it easy to build code which needs some 'cleandown' code executed (think of it as a try-finally block). Some more ex...
No ConcurrentList in .Net 4.0?
...read-safe, limited subset of IList<T>: in particular, one that would allow an Add and provide random read-only access by index (but no Insert, RemoveAt, etc., and also no random write access).
This was the goal of my ConcurrentList<T> implementation. But when I tested its performance in...
MVVM in WPF - How to alert ViewModel of changes in Model… or should I?
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RaisePropertyChanged("ViewModelCopyOfSomeProperty");
}
But typically this is only needed if more than one object will be making changes to the Model's data, which is not usually the case.
If you ever have a case where you don't actually have a reference to your Model property to attach t...
Save classifier to disk in scikit-learn
... Works like a charm! I was trying to use np.savez and load it back all along and that never helped. Thanks a lot.
– Kartos
Jan 29 '14 at 9:29
10
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Rails 2.3-style plugins and deprecation warnings running task in Heroku
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Yep, I realize that all the warnings came from my Heroku scripts and logs. I'll assume that (a) it's the plugin injections and (b) that the Heroku team will fix this before it becomes an actual problem.
– fearless_fool
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What is the purpose of class methods?
...sson was that Python is not Java , and so I've just spent a while turning all my Class methods into functions.
17 Answers
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URL rewriting with PHP
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You can essentially do this 2 ways:
The .htaccess route with mod_rewrite
Add a file called .htaccess in your root folder, and add something like this:
RewriteEngine on
RewriteRule ^/?Some-text-goes-here/([0-9]+)$ /picture.php?id=$1
Thi...
What is the difference between join and merge in Pandas?
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pandas.merge() is the underlying function used for all merge/join behavior.
DataFrames provide the pandas.DataFrame.merge() and pandas.DataFrame.join() methods as a convenient way to access the capabilities of pandas.merge(). For example, df1.merge(right=df2, ...) is equiva...
Method Resolution Order (MRO) in new-style classes?
...ject'>)
with A forced to come in resolution order only once and after all of its subclasses, so that overrides (i.e., C's override of member x) actually work sensibly.
It's one of the reasons that old-style classes should be avoided: multiple inheritance with "diamond-like" patterns just doesn...
What's the difference between dynamic (C# 4) and var?
...iteLine(s.Length);
and
string s = "abc";
Console.WriteLine(s.Length);
All that happened was that the compiler figured out that s must be a string (from the initializer). In both cases, it knows (in the IL) that s.Length means the (instance) string.Length property.
dynamic is a very different b...