大约有 47,000 项符合查询结果（耗时：0.0923秒） [XML]
What is in your Mathematica tool bag? [closed]
...ned this before, but the tool I find most useful is an application of Reap and Sow which mimics/extends the behavior of GatherBy:
SelectEquivalents[x_List,f_:Identity, g_:Identity, h_:(#2&)]:=
Reap[Sow[g[#],{f[#]}]&/@x, _, h][[2]];
This allows me to group lists by any criteria and tran...
How to determine if a list of polygon points are in clockwise order?
...gth (x2-x1). Notice the sign convention in x. Try this with some triangles and you'll soon see how it works.
– Beta
Jul 27 '09 at 14:20
75
...
Can a class member function template be virtual?
...would need to call a templatized virtual function, compilation is all done and the compiler cannot generate the appropriate instance anymore. Therefore you cannot have virtual member function templates.
However, there are a few powerful and interesting techniques stemming from combining polymorphi...
Is Redis just a cache?
I have been reading some Redis docs and trying the tutorial at http://try.redis-db.com/ . So far, I can't see any difference between Redis and caching technologies like Velocity or the Enterprise Library Caching Framework
...
What are the correct version numbers for C#?
...# known about at the time of this writing:
C# 1.0 released with .NET 1.0 and VS2002 (January 2002)
C# 1.2 (bizarrely enough); released with .NET 1.1 and VS2003 (April 2003). First version to call Dispose on IEnumerators which implemented IDisposable. A few other small features.
C# 2.0 released wit...
Are list-comprehensions and functional functions faster than “for loops”?
... in Python, is a list-comprehension, or functions like map() , filter() and reduce() faster than a for loop? Why, technically, they run in a C speed , while the for loop runs in the python virtual machine speed ?.
...
Abusing the algebra of algebraic data types - why does this work?
...ely, all unit types. They behave identically under algebraic manipulations and, more importantly, the amount of information present is still preserved.
You probably want a zero type as well. Haskell provides that as Void. There are no values whose type is zero, just as there is one value whose type ...
Algorithm for Determining Tic Tac Toe Game Over
I've written a game of tic-tac-toe in Java, and my current method of determining the end of the game accounts for the following possible scenarios for the game being over:
...
How do I select elements of an array given condition?
...e elements in y corresponding to elements in x that are greater than 1 and less than 5.
6 Answers
...
Why not use Double or Float to represent currency?
...lways been told never to represent money with double or float types, and this time I pose the question to you: why?
...