cannot unpack non-iterable NoneType object

问题遇到的现象和发生背景

运用pyautogui自动下载软件上的资料，为什么遍历代码列表，显示不可迭代的对象

用代码块功能插入代码，请勿粘贴截图

```python
import pyautogui
import pandas as pd
pyautogui.PAUSE = 1


#读取全部A股（标的股票代码）excel
data_read = pd.read_excel("F:\\gupiaoziliao\\全部A股.xlsx")
#清洗证券代码，去掉'.'和字母，只保留数字
code_column = list(data_read['证券代码'])
for i in range(len(code_column)):
    code_column[i] = code_column[i].split('.')[0]#先分割，再取子列表中的第一个元素
# 1.点击ifind图标
pyautogui.click(175,1055,button = 'left')

# 1.点击搜索框
def dianjidaimasousuokuang():
    #在搜索框内输入股票代码，并按回车键
    screen_img = pyautogui.screenshot()
    screen_img.save('F:\\PythonData\\image\\screen_img.png')
    left, top, width, height = pyautogui.locateOnScreen('F:\\PythonData\\image\\sousuokuang.png')
    center = pyautogui.center((left, top, width, height))
    pyautogui.click(center)
# 2.输入代码,并按回车键
def shurudaima(code):
    pyautogui.typewrite(code, 0.5)
    pyautogui.press('enter')

# 3.点击导出数据按钮
def dianjidaochushuju():
    screen_img = pyautogui.screenshot()
    screen_img.save('F:\\PythonData\\image\\screen_img.png')
    left, top, width, height = pyautogui.locateOnScreen('F:\\PythonData\\image\\daochushuju.png')
    center = pyautogui.center((left, top, width, height))
    pyautogui.click(center)

# 4. 点击路径输入框
def dianjibaocunlujing():
    screen_img = pyautogui.screenshot()
    screen_img.save('F:\\PythonData\\image\\screen_img.png')
    left, top, width, height = pyautogui.locateOnScreen('F:\\PythonData\\image\\baocun\\baocunweizhi.png')
    center = pyautogui.center((left, top, width, height))
    pyautogui.click(center)
# 5.输入保存路径
def shurulujing():
    pyautogui.typewrite('F:\\gupiaoziliao', 0.5)
    pyautogui.press('space')
# 6.点击转到按钮
def dianjizhuandao():
    screen_img = pyautogui.screenshot()
    screen_img.save('F:\\PythonData\\image\\screen_img.png')
    left, top, width, height = pyautogui.locateOnScreen('F:\\PythonData\\image\\baocun\\zhuandao.png')
    center = pyautogui.center((left, top, width, height))
    pyautogui.click(center)

# 7.点击文件名输入框
def dianjiwenjianming():
    screen_img = pyautogui.screenshot()
    screen_img.save('F:\\PythonData\\image\\screen_img.png')
    left, top, width, height = pyautogui.locateOnScreen(
        'F:\\PythonData\\image\\baocun\\wenjianming.png')
    center = pyautogui.center((left, top, width, height))
    pyautogui.click(center)
# 8.输入文件名，并点击空格键
def shuruwenjingming(code):
    pyautogui.typewrite(code+'-gongsijieshao', 0.5)
    pyautogui.press('space')

# 9.点击保存按钮
def dianjibaocunanniu():
    screen_img = pyautogui.screenshot()
    screen_img.save('F:\\PythonData\\image\\screen_img.png')
    left, top, width, height = pyautogui.locateOnScreen(
        'F:\\PythonData\\image\\baocun\\baocunjian.png')
    center = pyautogui.center((left, top, width, height))
    pyautogui.click(center)

#封装函数
i = 0
while i < len(code_column):
    # 1.点击搜索框
    dianjidaimasousuokuang()
    # 2.输入代码,并点击回车
    shurudaima(code_column[i])
    # 3.点击导出数据按钮
    dianjidaochushuju()
    #4.点击路径输入框
    dianjibaocunlujing()
    # 5.输入保存路径
    shurulujing()
    # 6.点击转到按钮
    dianjizhuandao()
    # 7.点击文件名输入框
    dianjiwenjianming()
    # 8.输入文件名，并点击空格键
    shuruwenjingming(code_column[i])
    # 9. 点击保存按钮
    dianjibaocunanniu()
    i += 1

运行结果及报错内容

Traceback (most recent call last):
  File "F:\PythonData\test.py", line 86, in 
    dianjidaochushuju()
  File "F:\PythonData\test.py", line 33, in dianjidaochushuju
    left, top, width, height = pyautogui.locateOnScreen('F:\\PythonData\\image\\daochushuju.png')
TypeError: cannot unpack non-iterable NoneType object

我想要达到的结果

说明屏幕上没找到daochushuju.png这张图片，返回了None。确认屏幕已经出现那个图片的页面，可以将confidence设置低一些

left, top, width, height = pyautogui.locateOnScreen('F:\PythonData\image\daochushuju.png',confidence=0.8)#还无法识别在继续减小一些
搜索后才出现导出界面的话，需要time.sleep等待一下

import time
def shurudaima(code):
    pyautogui.typewrite(code, 0.5)
    pyautogui.press('enter')
    time.sleep(2)#等待2s

• 这篇博客也许可以解决你的问题👉 ：TypeError: cannot unpack non-iterable NoneType object

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