Python returns 没有

Question

我有一个奇怪的问题。当我运行下面的代码并且图像不存在时，代码应该 return "None" 但由于某种原因没有打印任何内容。

PS：当我在虚拟机中运行这段代码一切正常，None 是 returned。

    try:
       inv_settings = pyautogui.locateOnScreen("settings.png", confidence=0.99)
    except Exception:
       pass

编辑：

import pyautogui

settings = not None
while settings is not None:
    try:
        inv_settings = pyautogui.locateOnScreen("settings.png", confidence=0.99)
        print(inv_settings)
    except Exception:
        pass

print("finished")

Answer 1

如果你想这样做 returns None 无论如何，只需删除 print.

def find():
    try:
        inv_settings = pyautogui.locateOnScreen("settings.png", confidence=0.99)
    except Exception:
        pass

Python 解释器不会打印出 None，因为这意味着没有任何有用的东西可以显示，但您仍然可以打印出实际的 return 值。

>>> find()
>>> # nothing was printed out because find() returned None
>>> print(find())
None
>>>

编辑：此外，您真的不应该禁止所有异常，因为这可能会阻止代码中的实际错误。在这种情况下，如果找到，则应设为 return True，否则应设为 False。否则，只是浪费时间和精力给出一个什么都不能告诉你的结果。

EDIT2：看起来您已经用完整代码更新了问题。我将为您提供更新后的代码和评论。

# all imports at the top :)
import pyautogui

# set `location` to None
location = None

# i'm assuming you want to keep locating until you find it so keep on
# checking until location isn't None anymore
while location is None:

    # i've checked the documentation and it seems that 
    # pyautogui.locateOnScreen either returns the location in
    # a named tuple `Box(left, top, width, height)` or it
    # raises pyautogui.ImageNotFoundException

    # here we try to get the location of "settings.png" on our screen
    try:
        location = pyautogui.locateOnScreen("settings.png", confidence=0.99)

    # we catch the exception if it can't find it. note we don't catch
    # all exceptions as it might hide other problems.
    except pyautogui.ImageNotFoundException:
        pass

print("finished")

Python returns 没有

Python returns nothing

python

pyautogui