While going through an excel file , I am interested in finding a way to generate a loop that iterates over rows in a specific pattern. For instance, I would like to read the initial three rows from my excel sheet (which are 0, 1, 2), followed by rows 10, 11, and 12 (which cor...
= 0: # the contours are stored as a NumPy array of (x,y) coordinates of the boundary points of the object largest_contour = max(contours, key=cv2.contourArea) perimeter = cv2.arcLength(largest_contour, True) # Perimeter in pixels im_array = r.plot() # plot a BGR numpy array of pr...
A=np.array([[1,2],[3,4]])B=np.array([[5,6],[7,8]])C=np.dot(A,B)print(C) Python Copy 这里我们使用了numpy的dot函数来计算两个矩阵的乘积。通过numpy提供的优化算法,这个运算可以在很短的时间内完成。 循环和numpy的性能比较 虽然numpy的优化能力很强,但在某些情况下,使用循环也许更快。比如...