multidimensional-array

问题 I have an NSMutableArray object that contains NSString objects. The mutable array object is called _usersToAddToFriendsList . When I am done adding NSString objects to it, I run the following code for Parse.com: [PFUser currentUser]; PFQuery *query = [PFQuery queryWithClassName:@"_User"]; [query whereKey:@"username" equalTo:_userSubmittedUsername]; [query getObjectInBackgroundWithId:_objectId block:^(PFObject *object, NSError *error) { object[@"friends"] = _usersToAddToFriendsList; [object

问题 I just started to use OpenMP to do parallel computing in C++. The program has a bad parallel performance. Since I don't know many multi-threading profiling tool (unlike simple gprof for single thread), I wrote a sample program to test the performance. I have a 2D matrix(N * N), with each element a 3d vector(x, y, z). I simply do a double for loop to set each value in the matrix: for (int i = 0; i < N; ++i) { for (int j = 0; j < N; ++j) { vectorStack[i][j] = VECTOR3D(1.0*i*i, 1.0*j*j, 1.0*i*j)

问题 Im looking for an example of multidimensional arrays. I have an array of thumbtails (9 for example) and a tablecellview of 4 thumbs pre row, giving me 3 rows. I want to create a new multidimensional array which will hold the 3 rows each row containing 4 arrays. Ive looked at many example for the past 3h but they all seem to suggest to use C-style coding and im not sure how to go about initialising them or if i need to release. Plus im using this in a tableview so im not sure if ill need to

问题 Here is the thing. I can completely understand a concept of a multidimensional array (let's consider 2D for a while) made by pointer to array to pointers and so on... We do something like this: // we can use dynamically defined size n and m int n = 3, m = 5 ; int **T = new int *[n]; for (int i = 0 ; i < n ; ++i) T[i] = new int[m]; What we got is: (Check if I'm right here) 3 blocks of memory of 5 ints, placed somewhere in memory One additional block of memory of same size as number of the

问题 Array mapping? I have $A= array("A1"=>array("x"=>1,"b"=>2,"d"=>3,"s"=>8), "A2"=>array("a"=>4,"b"=>3,"c"=>2,"d"=>1) ); OUTPUT(HTML): | a | b | c | d | x | s ------------------------------ A1 | 0 | 2 | 0 | 3 | 1 | 8 A2 | 4 | 3 | 2 | 1 | 0 | 0 Anyone know how to do this ? 回答1: Retrieve the keys $keys = array_unique(array_merge (array_keys($A['A1']), array_keys($A['A2']))); Then create the output echo " | "; echo implode(' | ', $keys) . "\n"; echo "\n"; foreach ($A as $name => $oneA) { echo "

问题 I have two numpy arrays, one an RGB image, one a lookup table of pixel values, for example: img = np.random.randint(0, 9 , (3, 3, 3)) lut = np.random.randint(0, 9, (1,3,3)) What I'd like is to know the x,y coordinate in lut of pixels whose values are common to img and lut , so I tried: for x in xrange(img.shape[0]): for y in xrange(img.shape[1]): print np.transpose(np.concatenate(np.where(lut == img[x,y]))) At this point, the problem is that img[x,y] , which will be in the form of [int_r, int

问题 I have two arrays like $a1= array( array('a'=>1,'b'=>2, 'c'=>3), // similar to $a2[0] array('a'=>3,'b'=>4, 'c'=>5), // similar to $a2[1] array('a'=>9,'b'=>6, 'c'=>9) ); $a2= array( array('a'=>1,'b'=>2, 'c'=>3), array('a'=>3,'b'=>4, 'c'=>5), array('a'=>5,'b'=>6, 'c'=>7), array('a'=>11,'b'=>4, 'c'=>13), array('a'=>14,'b'=>6, 'c'=>3) ); I want a resulting array that does't have common values like $arrayResult= array( array('a'=>9,'b'=>6, 'c'=>9),// from $a1[3] array('a'=>5,'b'=>6, 'c'=>7),//

问题 I am in a function where i fetch a multidimensional array from the parent container. The array fetched doesn't always have the same dimensions (it can be 1D, 2D, 3D, 4D, ...). I have for parameter a 1D array containing the coordinates, and the value. function(coordinates_array, value) { var muti_dim_array = getArrayByName(another_param); } Unfortunately, i can't do multi_dim_array[coordinates_array[0]][coordinates_array[1]][...] because the dimensions are not always the same. I could do a

问题 I'm new to cuda. I want to add up two 2d array into a third array. I use following code: cudaMallocPitch((void**)&device_a, &pitch, 2*sizeof(int),2); cudaMallocPitch((void**)&device_b, &pitch, 2*sizeof(int),2); cudaMallocPitch((void**)&device_c, &pitch, 2*sizeof(int),2); now my problem is that i dont want to use these array as flattened 2-d array all in my kernel code i want to di is use two for loop & put the result in the third array like __global__ void add(int *dev_a ,int *dev_b,int* dec

问题 I'm trying to convert all letters in a 2D char array into number. As results, I want a = 0, b=1, c=2, ... z=25. Then, I tried this as part of my code: char [][] letters = {{'i', 'u'}, {'a', 'g'}, {'e', 'k'}}; for (int i = 0; i < letters.length; i++) { for (int j = 0; j < letters[i].length; j++) { if (letters[i][j] >= 'a' && letters[i][j] <= 'z') { letters[i][j] = (char) ((letters[i][j] - 'a') + '0'); } } } The result of my code is not what I expected before. From 'a' to 'j', it worked well.