arrays
How to get a dimension (slice) from a multidimensional array
No. You could of course write a wrapper class that represents a slice, and has an indexer internally – but nothing inbuilt. The other approach would be to write a method that makes a copy of a slice and hands back a vector – it depends whether you want a copy or not. using System; … Read more
React render array of components
Have you consider using the new React Fragments? (in v16) This would be the simplest solution as it would by pass the whole array/key issue. If you need to pass key, then I’d suggest to simply require the components to have the keys. This is how React works, so I wouldn’t suggest you to hide … Read more
How to use realloc in a function in C
You want to modify the value of an int* (your array) so need to pass a pointer to it into your increase function: void increase(int** data) { *data = realloc(*data, 5 * sizeof int); } Calling code would then look like: int *data = malloc(4 * sizeof *data); /* do stuff with data */ increase(&data); … Read more
in Numpy, how to zip two 2-D arrays?
You can use dstack: >>> np.dstack((a,b)) array([[[0, 0], [1, 1], [2, 2], [3, 3]], [[4, 4], [5, 5], [6, 6], [7, 7]]]) If you must have tuples: >>> np.array(zip(a.ravel(),b.ravel()), dtype=(‘i4,i4’)).reshape(a.shape) array([[(0, 0), (1, 1), (2, 2), (3, 3)], [(4, 4), (5, 5), (6, 6), (7, 7)]], dtype=[(‘f0’, ‘<i4’), (‘f1’, ‘<i4’)]) For Python 3+ you need … Read more
How to find repeating sequence of characters in a given array?
Tongue-in-cheek O(NlogN) solution Perform an FFT on your string (treating characters as numeric values). Every peak in the resulting graph corresponds to a substring periodicity.
Numpy concatenate 2D arrays with 1D array
Try concatenating X_Yscores[:, None] (or X_Yscores[:, np.newaxis] as imaluengo suggests). This creates a 2D array out of a 1D array. Example: A = np.array([1, 2, 3]) print A.shape print A[:, None].shape Output: (3,) (3,1)
Why is creating an array with inline initialization so slow?
First of all, profiling at the C# level will give us nothing since it will show us the C# code line which takes longest to execute which is of course the inline array initialization, but for the sport: Now when we see the expected results, lets Observe the code at the IL Level and try … Read more
Why doesn’t Java have true multidimensional arrays?
but it seems that this is really not what one might have expected. Why? Consider that the form T[] means “array of type T”, then just as we would expect int[] to mean “array of type int”, we would expect int[][] to mean “array of type array of type int”, because there’s no less reason … Read more