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Can someone explain the traverse function in Haskell?
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traverse is the same as fmap, except that it also allows you to run effects while you're rebuilding the data structure.
Take a look at the example from the Data.Traversable documentation.
data Tree a = Empty | Leaf a | Node (Tree a) a (Tree a)
The Functor instance of Tr...
When to use ref and when it is not necessary in C#
...or C++. Changes to the value of the parameter itself won't be seen by the caller, but changes in the object which the reference points to will be seen.
When a parameter (of any kind) is passed by reference, that means that any changes to the parameter are seen by the caller - changes to the paramet...
Standard way to embed version into python package?
...is also used in lots of 3rd-party modules, so it's the quasi-standard.
Usually, __version__ is a string, but sometimes it's also a float or tuple.
Edit: as mentioned by S.Lott (Thank you!), PEP 8 says it explicitly:
Module Level Dunder Names
Module level "dunders" (i.e. names with two lea...
Flash CS4 refuses to let go
...roject, and it has many source files. I have a fairly heavily-used class, call it Jenine. I recently (and, perhaps, callously) relocated Jenine from one namespace to another. I thought we were ready - I thought it was time. The new Jenine was better in every way - she had lost some code bloat, she h...
Visual Studio 2010 - recommended extensions [closed]
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Free:
VsCommandBudy - Extend VS with external commands where really need them (Free)
PowerCommands - useful extensions for the Visual Studio 2010 adding additional functionality to various areas of the IDE.
DevExpress CodeRush Xpress - Coding assistance, Intellisense navigation,etc.
Ank...
Python logging not outputting anything
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@Ben where does it say that? All I can see is "The default level is WARNING, which means that only events of this level and above will be tracked, unless the logging package is configured to do otherwise."
– Omri Barel
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Qt events and signal/slots
... and handled by
any instance of a QObject subclass,
but they are especially relevant to
widgets. This document describes how
events are delivered and handled in a
typical application.
So events and signal/slots are two parallel mechanisms accomplishing the same things. In general, an eve...
What to use instead of “addPreferencesFromResource” in a PreferenceActivity?
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Still you need to call addPreferencesFromResource(int PreferencesID) if you want the app to be backwards compatible with api level erlier than 11 (Android 3.0). But I guess you could consider those old devices derecated as well.
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This project references NuGet package(s) that are missing on this computer
...nd in the process its relative folder structure changed.
So I had to edit all entries similar to the following one in my .csproj file from
<Import Project="..\packages\Microsoft.Bcl.Build.1.0.14\tools\Microsoft.Bcl.Build.targets" Condition="Exists('..\packages\Microsoft.Bcl.Build.1.0.14\tools...
How to install PyQt4 on Windows using pip?
...ld than just a pure python code package, which means it can be hard to install it from source.
Make sure you grab the correct Windows wheel file (python version, 32/64 bit), and then use pip to install it - e.g:
C:\path\where\wheel\is\> pip install PyQt4-4.11.4-cp35-none-win_amd64.whl
Should ...