Python 模块名称错误

Question

我从我制作的 Tkinter GUI 调用此脚本，我的一个变量无法从我的函数之一调用，我不明白为什么会这样？

我收到一个 NameError，当我按下一个按键来触发我的 Tag 函数之一时，'framevalues' 没有被定义。

提前致谢!

import cv2
import tkinter as tk
from tkinter.filedialog import askopenfilename


def main():
    framevalues = []
    count = 1
    selectedvideo = askopenfilename()
    selectedvideostring = str(selectedvideo)
    cap = cv2.VideoCapture(selectedvideo)
    length = int(cap.get(cv2.CAP_PROP_FRAME_COUNT))

    while (cap.isOpened()): 
        ret, frame = cap.read()

        # check if read frame was successful
        if ret == False:
                break
        # show frame first
        cv2.imshow('frame',frame)

        # then waitKey
        frameclick = cv2.waitKey(0) & 0xFF

        if frameclick == ord('a'):
            swingTag(cap)

        elif frameclick == ord('r'):
            rewindFrames(cap)

        elif frameclick == ord('s'):
            stanceTag(cap)

        elif frameclick == ord('d'):
            unsureTag(cap)

        elif frameclick == ord('q'):
            with open((selectedvideostring + '.txt'), 'w') as textfile:
                for item in framevalues:
                    textfile.write("{}\n".format(item))
            break

        else:
            continue

    cap.release()
    cv2.destroyAllWindows()

def stanceTag(cap):    
    framevalues.append('0' + ' ' + '|' + ' ' + str(int(cap.get(1))))
    print (str(int(cap.get(1))), '/', length) 
    print(framevalues)

def swingTag(cap):
    framevalues.append('1' + ' ' + '|' + ' ' + str(int(cap.get(1))))
    print (str(int(cap.get(1))), '/', length)
    print(framevalues) 

def unsureTag(cap):
    framevalues.append('-1' + ' ' + '|' + ' ' + str(int(cap.get(1))))
    print (str(int(cap.get(1))), '/', length) 
    print(framevalues)

def rewindFrames(cap):
    cap.set(1,((int(cap.get(1)) - 2)))
    print (int(cap.get(1)), '/', length) 
    framevalues.pop()
    print(framevalues)  






if __name__ == '__main__':
    # this is called if this code was not imported ... ie it was directly run
    # if this is called, that means there is no GUI already running, so we need to create a root
    root = tk.Tk()
    root.withdraw()
    main()

Answer 1

framevalues 是在 main() 中定义的局部变量，因此在其他函数中不可见。您可以将其设为全局，即在 main() 之前定义它，也可以将其作为普通函数参数从 main() 传递给其他函数，例如

def main():
    ...
    if frameclick == ord('a'):
        swingTag(cap, framevalues)  # pass it as a parameter
    ...
...
def swingTag(cap, framevalues):
    framevalues.append(...)  # now you are using local framevalues passed as parameter