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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...
How to redirect to a 404 in Rails?
...ou want to show a 404 page, create a render_404 method (or not_found as I called it) in ApplicationController like this:
def not_found
raise ActionController::RoutingError.new('Not Found')
end
Rails also handles AbstractController::ActionNotFound, and ActiveRecord::RecordNotFound the same way....
Speed comparison with Project Euler: C vs Python vs Erlang vs Haskell
... and the time changes to 11.1 seconds
in factorCount' you have needlessly called fromIntegral. A fix results in no change though (the compiler is smart, lucky for you).
You used mod where rem is faster and sufficient. This changes the time to 8.5 seconds.
factorCount' is constantly applying two extr...
How do I check if there are duplicates in a flat list?
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Use set() to remove duplicates if all values are hashable:
>>> your_list = ['one', 'two', 'one']
>>> len(your_list) != len(set(your_list))
True
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Remove not alphanumeric characters from string
...e them.
A backslash in the string needs escaping if it's to be taken literally:
"\\test\\red\\bob\\fred\\new".replace(/\W/g, '')
"testredbobfrednew" // output
Handling malformed strings
If you're not able to escape the input string correctly (why not?), or it's coming from some kind of untruste...
What does pylint's “Too few public methods” message mean
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The error basically says that classes aren't meant to just store data, as you're basically treating the class as a dictionary. Classes should have at least a few methods to operate on the data that they hold.
If your class looks like this:...
Getting number of elements in an iterator in Python
...ve an answer, this answer avoids instantiation of a list, and it is empirically faster by a constant than the reduce method listed above.
– Phillip Nordwall
Aug 2 '12 at 15:27
5
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ie8 var w= window.open() - “Message: Invalid argument.”
...n you look at the official documentation page, you see that Microsoft only allows the following arguments, If using that argument at all:
_blank
_media
_parent
_search
_self
_top
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Mediator Vs Observer Object-Oriented Design Patterns
...-to-many dependency between objects so that when one object changes state, all its dependents are notified and updated automatically.
The Mediator pattern:
Define an object that encapsulates how a set of objects interact. Mediator promotes loose coupling by keeping objects from referring to each o...
Constructor overload in TypeScript
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TypeScript allows you to declare overloads but you can only have one implementation and that implementation must have a signature that is compatible with all overloads. In your example, this can easily be done with an optional parameter...