multidimensional-array

问题 I saw a lot of articles and answers to other questions about slicing 3D lists in python, but I can't apply those methods to my case. I have a 3D list: list = [ [[0, 56, 78], [4, 86, 90], [7, 87, 34]], [[1, 49, 76], [0, 76, 78], [8, 60, 7]], [[9, 6, 58], [6, 57, 78], [10, 46, 2]] ] The the last 2 values of the 3rd dimension stay constant but change every time I rerun the code. What the code needs to do is find 2 specific pairs of those last 2 values and slice from one pair to the other. So for

问题 I want to find index of the nearest transition in a numpy ndarray of integers given a current index in an efficient manner. Transition means a change of value. For example, in the 2D array below, the right output for location (2,4) would be (3,6) (transition from Class 1 to Class 8) at the approximate distance of 2.236. In case of more than one optimum, returning any would suffice. import seaborn as sns import numpy as np step_size = [1,1] # size of step in each dimension arr = np.array([[6,6

问题 I want to find index of the nearest transition in a numpy ndarray of integers given a current index in an efficient manner. Transition means a change of value. For example, in the 2D array below, the right output for location (2,4) would be (3,6) (transition from Class 1 to Class 8) at the approximate distance of 2.236. In case of more than one optimum, returning any would suffice. import seaborn as sns import numpy as np step_size = [1,1] # size of step in each dimension arr = np.array([[6,6

问题 I'm using interpolate.interp2d() to fit a 2-D spline over a function. How can I get the first derivative of the spline w.r.t. each of the dependent variables? Here is my code so far, Z are the descrete points on a mesh-grid that I have from scipy import interpolate YY, XX = np.meshgrid(Y, X) f = interpolate.interp2d(AA, XX, Z, kind='cubic') So, I need df/dx and df/dy. Note also that my Y-grid is not evenly spaced. I guess I can numerically differentiate Z and then fit a new spline, but it

问题 Let's assume I have an array of elements, which are arrays themselves, like so: $array = [ ['foo' => 'ABC', 'bar' => 'DEF'], ['foo' => 'ABB', 'bar' => 'DDD'], ['foo' => 'BAC', 'bar' => 'EFF'], ]; To set the values of the foo field as the key of the array I could do this: foreach ($array as $element) { $new_array[$element['foo']] = $element; } $array = $new_array; The code is naturally trivial, but I've been wondering whether there's an in-built that can do the same for me. 回答1: Notice array

问题 numpy provides three handy routines to turn an array into at least a 1D, 2D, or 3D array, e.g. through numpy.atleast_3d I need the equivalent for one more dimension: atleast_4d . I can think of various ways using nested if statements but I was wondering whether there is a more efficient and faster method of returning the array in question. In you answer, I would be interested to see an estimate (O(n)) of the speed of execution if you can. 回答1: The np.array method has an optional ndmin keyword

问题 numpy provides three handy routines to turn an array into at least a 1D, 2D, or 3D array, e.g. through numpy.atleast_3d I need the equivalent for one more dimension: atleast_4d . I can think of various ways using nested if statements but I was wondering whether there is a more efficient and faster method of returning the array in question. In you answer, I would be interested to see an estimate (O(n)) of the speed of execution if you can. 回答1: The np.array method has an optional ndmin keyword

问题 i want to explode a string two time and make a multi-dimensional array. $data = "i love funny movies \n i love stackoverflow dot com \n i like rock song"; $data = explode("\n", $data); so a print_r($data); will output: Array ( [0] => i love funny movies [1] => i love stackoverflow com [2] => i like rock song ) now if i do like this: $line_data = explode(" ", $data); // explode $data variable by spaces. a print_r($line_data); will give me this: Array ( [0] => i [1] => love [2] => funny [3] =>

问题 i want to explode a string two time and make a multi-dimensional array. $data = "i love funny movies \n i love stackoverflow dot com \n i like rock song"; $data = explode("\n", $data); so a print_r($data); will output: Array ( [0] => i love funny movies [1] => i love stackoverflow com [2] => i like rock song ) now if i do like this: $line_data = explode(" ", $data); // explode $data variable by spaces. a print_r($line_data); will give me this: Array ( [0] => i [1] => love [2] => funny [3] =>

问题 I have an associative multidimensional (dynamic length of dimensions) array. It originally comes from JSON data, but I understand that just makes things harder so I convert it using json_decode($original_data, true) . I'm interested to convert it to a clickable CSV file like echo '<a href="data:application/csv, ' . $data . '">Click to download</a>' . I've tried many code variations, one of which I found online in https://coderwall.com/p/zvzwwa/array-to-comma-separated-string-in-php because