array

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 由 翻译 强力驱动 问题: Can I define in C++ an array operator that takes multiple arguments? I tried it like this: const T & operator []( const int i , const int j , const int k ) const { return m_cells [ k * m_resSqr + j * m_res + i ]; } T & operator []( const int i , const int j , const int k ){ return m_cells [ k * m_resSqr + j * m_res + i ]; } But I'm getting this error: error C2804 binary operator '[' has too many parameters 回答1: Nope, you can't overload operator[] to accept multiple arguments. You instead can overload operator() . See How do I

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I'm just learning C and was wondering which one of these I should use in my main method. Is there any difference? Edit: So which one is more common to use? 回答1: As you are just learning C, i recommend you to really try to understand the differences between arrays and pointers first instead of the common things. In the area of parameters and arrays, there are a few confusing rules that should be clear before going on. First, what you declare in a parameter list is treated special. There are such situations where things don't make sense as a

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Assuming I have an ArrayList ArrayList<MyClass> myList; And I want to call toArray, is there a performance reason to use MyClass[] arr = myList.toArray(new MyClass[myList.size()]); over MyClass[] arr = myList.toArray(new MyClass[0]); ? I prefer the second style, since it's less verbose, and I assumed that the compiler will make sure the empty array doesn't really get created, but I've been wondering if that's true. Of course, in 99% of the cases it doesn't make a difference one way or the other, but I'd like to keep a consistent style

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I want to create a constant static array to be used throughout my Objective-C implementation file similar to something like this at the top level of my ".m" file: static const int NUM_TYPES = 4; static int types[NUM_TYPES] = { 1, 2, 3, 4 }; I plan on using NUM_TYPES later on in the file so I wanted to put it in a variable. However, when I do this, I get the error "Variably modified 'types' at file scope" I gather that this may have something to do with the array size being a variable (I don't get this message when I put an integer literal

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Surely a 0d array is scalar, but Numpy does not seem to think so... am I missing something or am I just misunderstanding the concept? >>> foo = numpy.array(1.11111111111, numpy.float64) >>> numpy.ndim(foo) 0 >>> numpy.isscalar(foo) False >>> foo.item() 1.11111111111 回答1: One should not think too hard about it. It's ultimately better for the mental health and longevity of the individual. The curious situation with Numpy scalar-types was bore out of the fact that there is no graceful and consistent way to degrade the 1x1 matrix to scalar types

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: An interesting interview question that a colleague of mine uses: Suppose that you are given a very long, unsorted list of unsigned 64-bit integers. How would you find the smallest non-negative integer that does not occur in the list? FOLLOW-UP: Now that the obvious solution by sorting has been proposed, can you do it faster than O(n log n)? FOLLOW-UP: Your algorithm has to run on a computer with, say, 1GB of memory CLARIFICATION: The list is in RAM, though it might consume a large amount of it. You are given the size of the list, say N, in

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have an array in Perl: my @my_array = ("one","two","three","two","three"); How do I remove the duplicates from the array? 回答1: You can do something like this as demonstrated in perlfaq4 : sub uniq { my %seen; grep !$seen{$_}++, @_; } my @array = qw(one two three two three); my @filtered = uniq(@array); print "@filtered\n"; Outputs: one two three If you want to use a module, try the uniq function from List::MoreUtils 回答2: The Perl documentation comes with a nice collection of FAQs. Your question is frequently asked: % perldoc -q duplicate

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have a string in a Bash shell script that I want to split into an array of characters, not based on a delimiter but just one character per array index. How can I do this? Ideally it would not use any external programs. Let me rephrase that. My goal is portability, so things like sed that are likely to be on any POSIX compatible system are fine. 回答1: Try echo "abcdefg" | fold -w1 Edit: Added a more elegant solution suggested in comments. echo "abcdefg" | grep -o . 回答2: You can access each letter individually already without an array

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: Why do I get this error message? ValueError: setting an array element with a sequence. Thank you Z=np.array([1.0,1.0,1.0,1.0]) def func(TempLake,Z): A=TempLake B=Z return A*B Nlayers=Z.size N=3 TempLake=np.zeros((N+1,Nlayers)) kOUT=np.zeros(N+1) for i in xrange(N): kOUT[i]=func(TempLake[i],Z) 回答1: You're getting the error message ValueError: setting an array element with a sequence. because you're trying to set an array element with a sequence. I'm not trying to be cute, there -- the error message is trying to tell you exactly what the

可以将文章内容翻译成中文,广告屏蔽插件可能会导致该功能失效(如失效，请关闭广告屏蔽插件后再试): 问题: I have two different arrays, one with strings and another with ints. I want to concatenate them, into one array where each column has the original datatype. My current solution for doing this (see below) converts the entire array into dtype = string, which seems very memory inefficient. combined_array = np.concatenate((A, B), axis = 1) Is it possible to mutiple dtypes in combined_array when A.dtype = string and B.dtype = int ? 回答1: One approach might be to use a record array . The "columns" won't be like the columns of standard numpy arrays,