multidimensional-array

问题 I'm new to C/C++ and I've been cracking my head but still got no idea how to make an "structure" like this It's supposed to be a 3D dynamic array using pointers. I started like this, but got stuck there int x=5,y=4,z=3; int ***sec=new int **[x]; It would be enough to know how to make it for a static size of y and z; Please, I'd appreciate that you help me. Thanks in advance. 回答1: To create dynamically 3D array of integers, it's better you understand 1D and 2D array first. 1D array : You can

问题 Let's say I have two dimensional array that represents simple matrix int[,] matrix= new int[,] { { 1, 2 }, { 3, 4 }, { 1, 2 }, { 7, 8 } }; It looks like that 1 2 3 4 1 2 7 8 Is there any way to delete duplicate rows using LINQ and make array to look like this? 1 2 3 4 7 8 回答1: This is not really Linq, but you can define some helper method as if they were Linq methods. The simpler algorithm should be: Convert to a list of list Apply a distinct with a custom comparer Rebuild another array This

问题 Let's say I have two dimensional array that represents simple matrix int[,] matrix= new int[,] { { 1, 2 }, { 3, 4 }, { 1, 2 }, { 7, 8 } }; It looks like that 1 2 3 4 1 2 7 8 Is there any way to delete duplicate rows using LINQ and make array to look like this? 1 2 3 4 7 8 回答1: This is not really Linq, but you can define some helper method as if they were Linq methods. The simpler algorithm should be: Convert to a list of list Apply a distinct with a custom comparer Rebuild another array This

问题 I would like to create a 3D array in Python (2.7) to use like this: distance[i][j][k] And the sizes of the array should be the size of a variable I have. (n*n*n) I tried using: distance = [[[]*n]*n] but that didn't seem to work. Any ideas? Thanks a lot! EDIT: I can only use the deafult libraries, and the method of multiplying (ie [[0]*n]*n) wont work because they are linked to the same pointer and I need all of the values to be individual EDIT2: Already solved by answer below. 回答1: You should

问题 I have this multidimensional array: Array ( [0] => Array ( [0] => 2012-02-26 07:15:00 ) [1] => Array ( [0] => 2012-02-26 17:45:00 [1] => 2012-02-26 18:55:00 ) [2] => Array ( [0] => 2012-02-26 18:55:00 [1] => 2012-02-26 17:45:00 ) [3] => Array ( [0] => 2012-02-26 18:57:00 [1] => 2012-02-26 17:45:00 [2] => 2012-02-26 18:55:00 ) When I count subarrays I get this 1,2,2,3. How could I receive it in 3,2,2,1? I need to get for example last 3 subarrays with the highest subarray count (DESC, it means

问题 This question already has answers here : How can I sort arrays and data in PHP? (11 answers) Closed 5 years ago . I know there are some other topics about sorting with multiple criteria, but they don't fix my problem. Let's say I have this array: Array ( [0] => Array ( [uid] => 1 [score] => 9 [endgame] => 2 ) [1] => Array ( [uid] => 2 [score] => 4 [endgame] => 1 ) [2] => Array ( [uid] => 3 [score] => 4 [endgame] => 100 ) [3] => Array ( [uid] => 4 [score] => 4 [endgame] => 70 ) ) I want to

问题 Since ProtoBuf-Net does not support serializing/deserializing multi-dimensional arrays, how would I go about managing my arrays? 回答1: This is essentially a limitation of the underlying protobuf wire format; it only supports single-dimension arrays. Two options leap to mind; firstly, send it as a linear array, and send the dimensions separately. You could also represent it as a list of objects that each has an array - essentially a jagged array, but with an intermediate step. Of the two, the

问题 I have a list like this : a = ((4.0, 4, 4.0), (3.0, 3, 3.6), (3.5, 6, 4.8)) I want an outcome like this ( EVERY first element in the list) : 4.0, 3.0, 3.5 I tried a[::1][0], but it doesn't work I'm just start learning Python weeks ago. Python version = 2.7.9 回答1: You can get the index [0] from each element in a list comprehension >>> [i[0] for i in a] [4.0, 3.0, 3.5] Also just to be pedantic, you don't have a list of list , you have a tuple of tuple . 回答2: use zip columns = zip(*rows)

问题 Suppose I have this multidimensional array: float[][,] vertices = { new float[,]{ {0f, 1.28f}, {1.28f, 2.56f}, {3.84f, 2.56f}, {5.12f, 1.28f}, {3.84f, 0f}, {1.28f, 0f}, {0f, 1.28f} }, new float[,]{ {0f, 3.83f}, {1.27f, 5.12f}, {3.87f, 5.12f}, {5.12f, 3.83f}, {5.12f, 1.26f}, {3.87f, 0f}, {1.27f, 0f}, {0f, 1.26f}, {0f, 3.83f} } }; Now, I want to convert each subarray to an array of type Vector2[] where Vector2 is a public class, which simply contains x and y properties: public class Vector2 {

问题 for(int i = 0; i<100; i++) for(int j = 0; j<100; j++) array[j][i] = 0; // array[i][j] = 0; My professor said it was much more costly to initialize a two dimensional array in the first way as opposed to the second. Can someone explain what is going on underneath the hood which makes that the case? Or, do the two means of initialization have equal performance? 回答1: As @dlev mentioned, this is due to locality of reference and has to do with how the physical hardware in the computer works. Inside