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Callback functions in C++
In C++, when and how do you use a callback function?
10 Answers
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What's the deal with a leading underscore in PHP class methods?
... { to give it some extra weight.
I've never heard of developers prefacing all their methods with underscores, so I can't begin to explain what causes that.
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Can “using” with more than one resource cause a resource leak?
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No.
The compiler will generate a separate finally block for each variable.
The spec (§8.13) says:
When a resource-acquisition takes the form of a
local-variable-declaration, it is possible to acquire multiple
resources of a given type. A using statement of the...
How to add an integer to each element in a list?
...ition, but if you have a more complex function that you needed to apply to all the elements then map may be a good fit.
In your example it would be:
>>> map(lambda x:x+1, [1,2,3])
[2,3,4]
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Swift: #warning equivalent
...builds clean in production, but I get a warning in development that essentially reminds me I'm in dev mode - using different URLs, timeouts, other settings etc. Arie's suggestion above lets me do this, your technique just flags everything. That said, this technique has its use for sure so I up voted...
Python: Is it bad form to raise exceptions within __init__?
...t have been designed with exception safety in mind, the destructor is not called if an exception is thrown in the constructor of an object (meaning that the initialization of the object is incomplete). This is often not the case in scripting languages, such as Python. For example, the following code...
Event system in Python
...r methods', which is a
simple implementation of the Observer pattern.
Basically, the handler methods (callables) are stored in an array and are each called when the event 'fires'.
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The disadvantage of Observer event systems is that you can only register the handlers on the actual Ev...
Delete column from pandas DataFrame
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This answer isn't really correct - the pandas developers didn't, but that doesn't mean it is hard to do.
– wizzwizz4
Sep 30 '17 at 9:42
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git command to move a folder inside another
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Command:
$ git mv oldFolderName newFolderName
It usually works fine.
Error "bad source ..." typically indicates that after last commit there were some renames in the source directory and hence git mv cannot find the expected file.
The solution is simple - just commit before ...
Ways to implement data versioning in MongoDB
... approach would be to store diffs. Because the display of these diffs is really a special action, I would put the diffs in a different "history" collection.
I would use the different collection to save memory space. You generally don't want a full history for a simple query. So by keeping the histo...