Question

我正在创建一个Python类，但似乎我无法使构造函数类正常工作。这是我的班级：

class IQM_Prep(SBconcat):
    def __init__(self,project_dir):
        self.project_dir=project_dir #path to parent project dir
        self.models_path=self.__get_models_path__() #path to parent models dir
        self.experiments_path=self.__get_experiments_path__()     #path to parent experiemnts dir

    def __get_models_path__(self):
        for i in os.listdir(self.project_dir):
            if i=='models':
                models_path=os.path.join(self.project_dir,i)
        return models_path

    def __get_experiments_path__(self):
        for i in os.listdir(self.project_dir):
            if i == 'experiments':
                experiments_path= os.path.join(self.project_dir,i)
        return experiments

初始化此课时：

project_dir='D:\\MPhil\\Model_Building\\Models\\TGFB\\Vilar2006\\SBML_sh_ver\\vilar2006_SBSH_test7\\Python_project'

IQM= Modelling_Tools.IQM_Prep(project_dir)

我收到以下错误：

Traceback (most recent call last):

  File "<ipython-input-49-7c46385755ce>", line 1, in <module>
    runfile('D:/MPhil/Python/My_Python_Modules/Modelling_Tools/Modelling_Tools.py', wdir='D:/MPhil/Python/My_Python_Modules/Modelling_Tools')

  File "C:\Anaconda1\lib\site-packages\spyderlib\widgets\externalshell\sitecustomize.py", line 585, in runfile
    execfile(filename, namespace)

  File "D:/MPhil/Python/My_Python_Modules/Modelling_Tools/Modelling_Tools.py", line 1655, in <module>
    import test

  File "test.py", line 19, in <module>
    print parameter_file

  File "Modelling_Tools.py", line 1536, in __init__
    self.models_path=self.__get_models_path__() #path to parent models dir

  File "Modelling_Tools.py", line 1543, in __get_models_path__
    return models_path

UnboundLocalError: local variable 'models_path' referenced before assignment

Modelling_Tools是我的自定义模块的名称。

Answer 1

基于追溯，似乎要么：

def __get_models_path__(self):
    for i in os.listdir(self.project_dir):  # 1. this never loops; or
        if i=='models':  # 2. this never evaluates True
            models_path=os.path.join(self.project_dir,i)  # hence this never happens
    return models_path  # and this causes an error

您应该查看os.listdir(self.project_dir)的结果，找出原因;目录为空或其中的任何内容都未命名为models。你可以初始化，例如在方法开始时models_path = None，但这只会将问题隐藏起来直到以后。

Sidenote ：根据我的评论，您应该查看style guide，特别是有关方法的命名约定...

Answer 2

XDocument xdoc = new XDocument(); foreach (DataGridViewRow dr in dataGridView1.Rows) { XElement line = new XElement("line"); XElement itemid = new XElement("field", dr.Cells["Item ID"].Value.ToString()); itemid.Add(new XAttribute("name", "item_id")); line.Add(itemid); XElement itemname = new XElement("field", dr.Cells["Item Name"].Value.ToString()); itemname.Add(new XAttribute("name", "item_name")); line.Add(itemname); XElement cost = new XElement("field", dr.Cells["Cost"].Value.ToString()); cost.Add(new XAttribute("name", "cost")); line.Add(cost); xdoc.Add(line); break; } xdoc.Save(@"C:\xmltest\test3.xml");仅在以下情况下初始化：

models_path有一些文件/目录和
此文件/目录之一的名称为self.project_dir

如果其中一个条件未满，则models未初始化。

UnboundLocalError初始化python类

2 个答案: