小编Ant*_*ano的帖子

我想展示几张图片,在两者之间暂停.我试过waitKey,等待用户按ESC,但它似乎没有工作.

import numpy as np
import cv2

img = cv2.imread('image1.jpg',0)
cv2.imshow('image',img)


# here it should be the pause
k = cv2.waitKey(0)
if k == 27:         # wait for ESC key to exit
    cv2.destroyAllWindows()

img = cv2.imread('image2.jpg',0)
    cv2.imshow('image',img)

有什么建议吗？

提前致谢

假设我有一个字符串text ="Hello".我想分别打印字符串的奇数/偶数位置.我已设法按正常顺序执行此操作(请参阅下面的代码).

现在的问题是我想做同样但从最后开始.也就是说,奇数现在等于"le",甚至等于"olH".

    text = "Hello"

    # Normal order
    odd = text[1::2] # --> "el"
    even = text[0::2] # --> "Hlo"

    # Reverse order (WRONG)
    odd = text[-2::2] 
    even = text[-1::2]