Python 测试运行失败：局部变量''；分配前参考

长期读者，第一次海报

我一直致力于在我的工作场所建立第一套自动化系统，同时自学我的第一门编程语言。最终目标是建立一个Sikuli脚本，以便在夜间运行测试

我不断地遇到错误，感觉自己对python的基本原理缺乏理解，周围也没有人教我

函数

do_math

解析.csv文件，进行一些计算，并以元组形式返回这些变量。然后，我将这些结果分配到一个变量中，并尝试比较它们，但我一直遇到：

Test Run Failed: local variable 'D2LAverage' referenced before assignment

我曾尝试在许多不同的地方分配d2lavarge，使其成为全局的，返回列表与元组，但它总是被卡住

-调用上面的

dou\u math

  do_math()
  results = do_math()
  
  # Specify the path
  path = 'C:/Users/AeosFactory/Desktop/'

  # Specify the file name
  file_name = "Latency_Results" + "_" + str(datetime.datetime.now().strftime('%Y-%m-%d_%H_%M_%S')) + ".txt"

  # Create a file at specified location and do comparison
  with open (os.path.join(path, file_name), 'a+') as Latency_Results:
    if results[0] <= 85:
      Latency_Results.write("Pass" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, D2L Average:" + " " + str(round(D2LAverage,2)) + '\n')
    else: 
      Latency_Results.write("Fail" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, D2L Average:" + " " + str(round(D2LAverage,2)) + '\n')
    if D2Lstd <= 10:
      Latency_Results.write("Pass" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, D2L Standard Deviation:" + " " + str(round(D2Lstd,2)) + '\n')
    else:
      Latency_Results.write("Fail" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, D2L Standard Deviation:" + " " + str(round(D2Lstd,2)) + '\n') 

    if L2DAverage <= 85:
      Latency_Results.write("Pass" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, L2D Average:" + " " + str(round(L2DAverage,2)) + '\n')
    else:
      Latency_Results.write("Fail" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, L2D Average:" + " " + str(round(L2DAverage,2)) + '\n') 
    if L2Dstd <= 10:
      Latency_Results.write("Pass" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, L2D Standard Deviation:" + " " + str(round(L2Dstd,2)) + '\n' + '\n')
    else:
      Latency_Results.write("Fail" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, L2D Standard Deviation:" + " " + str(round(L2Dstd,2)) + '\n' + '\n')

do_math（）
结果=做数学（）
#指定路径
路径='C:/Users/AeosFactory/Desktop/'
#指定文件名
file_name=“Latency_Results”+“”+str（datetime.datetime.now（）.strftime（“%Y-%m-%d_%H_%m_%S”）+”.txt
#在指定位置创建文件并进行比较
以open（os.path.join（path，file_name），“a+”作为延迟结果：
如果结果[0]（全局变量除外），则python文件之间不会共享变量。如果您查看
start\u script.py
中的内容，您永远不会在任何地方定义D2LAverage。当您试图在if语句中使用它时，会引发一个错误，因为Python“不知道您在说什么”。我认为让您感到困惑的是，返回值的名称暴露在调用函数的范围内。返回的只是返回值本身

在
do_math（）
的末尾有一行
return D2LAverage、D2Lstd、L2DAverage、L2Dstd
，因为Python只允许每个函数返回一个值，这些值被打包到一个元组中

在
start\u script.py
中调用
do\u math（）
两次


一次，不捕获返回值
一旦将返回值分配给
结果

如果您只关心函数的结果，那么可能需要删除对它的第一次调用

要访问由
do_math（）
返回的单个值，您可以通过将
results[0]
索引到元组直接访问所需值，或者使用元组解包将4个返回值分配给单个变量，类似于
D2LAverage、D2Lstd、L2DAverage、，L2Dstd=results
在为
结果[0]
执行此操作后，您似乎忘记了为
结果编制索引。您可以尝试保持这种方式，方法是按如下方式解压缩结果：
D2LAverage，D2Lstd，L2DAAverage，L2Dstd=results
调用
do\uMath
后替换
结果[0]
带有
D2LAverage
  do_math()
  results = do_math()
  
  # Specify the path
  path = 'C:/Users/AeosFactory/Desktop/'

  # Specify the file name
  file_name = "Latency_Results" + "_" + str(datetime.datetime.now().strftime('%Y-%m-%d_%H_%M_%S')) + ".txt"

  # Create a file at specified location and do comparison
  with open (os.path.join(path, file_name), 'a+') as Latency_Results:
    if results[0] <= 85:
      Latency_Results.write("Pass" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, D2L Average:" + " " + str(round(D2LAverage,2)) + '\n')
    else: 
      Latency_Results.write("Fail" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, D2L Average:" + " " + str(round(D2LAverage,2)) + '\n')
    if D2Lstd <= 10:
      Latency_Results.write("Pass" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, D2L Standard Deviation:" + " " + str(round(D2Lstd,2)) + '\n')
    else:
      Latency_Results.write("Fail" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, D2L Standard Deviation:" + " " + str(round(D2Lstd,2)) + '\n') 

    if L2DAverage <= 85:
      Latency_Results.write("Pass" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, L2D Average:" + " " + str(round(L2DAverage,2)) + '\n')
    else:
      Latency_Results.write("Fail" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, L2D Average:" + " " + str(round(L2DAverage,2)) + '\n') 
    if L2Dstd <= 10:
      Latency_Results.write("Pass" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, L2D Standard Deviation:" + " " + str(round(L2Dstd,2)) + '\n' + '\n')
    else:
      Latency_Results.write("Fail" + " - " + "4 Screens, Image Mode 1, Surgery, Live, HC, L2D Standard Deviation:" + " " + str(round(L2Dstd,2)) + '\n' + '\n')