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Android AsyncTask threads limits?
...ery time user logs in to the system, I also use database in the phone. For all those operations (updates, retrieving data from db and etc.) I use async tasks. As up till now I didn't see why I shouldn't use them, but recently I experienced that if I do some operations some of my async tasks simply s...
Mean per group in a data.frame [duplicate]
... the many ways to specify the variables to act on. Here, vars(-Month) says all variables except Month.
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Why does int i = 1024 * 1024 * 1024 * 1024 compile without error?
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@WouterLievens, overflow is normally an "unusual" condition, if not an outright error condition. It is a result of finite-precision math, which most people are not intuitively expecting to happen when they do math. In some cases, like -1 + 1, it's harmless;...
Array.Copy vs Buffer.BlockCopy
...uffer from one or more severe technical flaws, including not moving memory allocations out of the test loops (which introduces severe GC artifacts), not testing variable vs. deterministic execution flows, JIT warmup, and not tracking intra-test variability. In addition, most answers did not test the...
Optimistic vs. Pessimistic locking
...to the database for your session. In this situation the client cannot actually maintain database locks as the connections are taken from a pool and you may not be using the same connection from one access to the next.
Pessimistic Locking is when you lock the record for your exclusive use until you...
How can I use a DLL file from Python?
...hlapi32.dll")
# Set up prototype and parameters for the desired function call.
# HLLAPI
hllApiProto = ctypes.WINFUNCTYPE (
ctypes.c_int, # Return type.
ctypes.c_void_p, # Parameters 1 ...
ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p) # ... thru 4.
hllApiParams = (...
LINQ query on a DataTable
...s.Cast<DataRow>().Where(myRow => (int)myRow["RowNo"] == 1). Personally, I don't find the call to AsEnumerable() any more complicated than the call to Cast<DataRow>(). As far as I know, the performance is the same, so it's just a matter of preference.
– Collin K
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Git Bash doesn't see my PATH
...ecutable names without extensions. In my case, I wanted to execute a file called cup.bat. In a Windows shell, typing cup would be enough. Bash doesn't work this way, it wants the full name. Typing cup.bat solved the problem. (I wasn't able to run the file though, since apparently bash couldn't under...
[A]System.Web.WebPages.Razor.Configuration.HostSection cannot be cast to… web.config issue
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I am using VS2013, MVC 5.2.2.0, Web Api 2. I have just changed the all versions from 2.0.0.0 to 3.0.0.0 of the following section of Web.config resides inside the View folder of my project.
<configSections>
<sectionGroup name="system.web.webPages.razor" type="System.Web.WebPages.Raz...
Why should hash functions use a prime number modulus?
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Usually a simple hash function works by taking the "component parts" of the input (characters in the case of a string), and multiplying them by the powers of some constant, and adding them together in some integer type. So for e...