Python 正在更正脚本中的属性和/或UnboundLocalError

此脚本接受用户输入（对于员工），并通过SQLAlchemy将其添加到sqlite3.db中。直到我在年龄字段的add_data方法中添加了

try:except

子句（计划在其他字段中添加更多try/except子句），它才开始工作。年龄字段需要是用户选择的整数。我意识到我需要一种方法来捕获由于用户向字段中添加字符串而不是数字而导致的任何错误。相关代码

try:
        self.age = self.age_var.get()
    except ValueError:
        showinfo("Error:", "Please Enter A Number In Age Field.")

from datetime import datetime
from Tkinter import *
from tkMessageBox import *
import sqlite3, sqlalchemy
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, DateTime, Integer, String, MetaData
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

# map classes to tables through Base Class
Base = declarative_base()


class Employee(Base):
    __tablename__ = 'employee'
    id = Column(Integer, primary_key=True)
    name = Column(String(250))
    age = Column(Integer)
    address = Column(String(250))
    city = Column(String(10))
    state = Column(String(2))
    zip = Column(Integer)
    ssn = Column(String(12))
    phone = Column(String(12))
    cell = Column(String(12))

# create engine for Session connection
engine = create_engine('sqlite:///employee.db')

# create all tables in engine ('CREATE TABLE' in raw SQL)
Base.metadata.create_all(engine)

# create configured 'Session' class
Session = sessionmaker(bind=engine)

# create session
session = Session()


class GUI:
    def __init__(self, parent):
        self.parent = parent

        # create top frame
        frame = Frame(parent)
        frame.pack(expand=YES, fill=BOTH, padx=5, pady=5)

        # create bottom frame
        btm_frame = Frame(parent, relief=SUNKEN, borderwidth=1)
        btm_frame.pack(side=BOTTOM, expand=YES, fill=BOTH, padx=5, pady=5)

        # create datetime object
        d = datetime.today()
        date = d.strftime("%Y-%m-%d")


#------------------------Create Labels-------------------------------#


        # label to display date
        date_label = Label(btm_frame, text=date)
        date_label.pack(side=LEFT)

        # name label
        name_label = Label(frame, text="Enter Name:")
        name_label.grid(row=0, sticky=W)

        # age label
        age_label = Label(frame, text="Enter Age:")
        age_label.grid(row=1, sticky=W)

        # address label
        addr_label = Label(frame, text="Enter Address:")
        addr_label.grid(row=2, sticky=W)

        # city label
        city_label = Label(frame, text="Enter City:")
        city_label.grid(row=3, sticky=W)

        # state label
        state_label = Label(frame, text="Enter State:")
        state_label.grid(row=4, sticky=W)

        # zip code label
        zip_label = Label(frame, text="Enter Zip Code:")
        zip_label.grid(row=5, sticky=W)

        # ssn label
        ssn_label = Label(frame, text="Enter Social Security #:")
        ssn_label.grid(row=6, sticky=W)

        # phone label
        phone_label = Label(frame, text="Enter Phone #:")
        phone_label.grid(row=7, sticky=W)

        # cell label
        cell_label = Label(frame, text="Enter Cell #:")
        cell_label.grid(row=8, sticky=W)


#----------------------Create Vars and Entry-------------------------#


        # name variable and entry
        self.name_var = StringVar()
        self.e1 = Entry(frame, textvariable=self.name_var)
        self.e1.grid(row=0, column=1)

        # age variable and entry
        self.age_var =  IntVar()
        self.e2 = Entry(frame, textvariable=self.age_var)
        self.e2.grid(row=1, column=1)

        # address variable and entry
        self.address_var = StringVar()
        self.e3 = Entry(frame, textvariable=self.address_var)
        self.e3.grid(row=2, column=1)

        # city variable and entry
        self.city_var = StringVar()
        self.e4 = Entry(frame, textvariable=self.city_var)
       self.e4.insert(0, "Roanoke")        # insert default value
       self.e4.grid(row=3, column=1)

        # state variable and entry
        self.state_var = StringVar()
        self.e5 = Entry(frame, textvariable=self.state_var)
        self.e5.insert(0, "VA")             # insert default value
        self.e5.grid(row=4, column=1)

        # zip code variable and entry
        self.zip_var = IntVar()
        self.e6 = Entry(frame, textvariable=self.zip_var)
        self.e6.grid(row=5, column=1)

        # s.s.n variable and entry
        self.ssn_var = StringVar()
        self.e7 = Entry(frame, textvariable=self.ssn_var)
        self.e7.grid(row=6, column=1)

    # phone variable and entry
        self.phone_var = StringVar()
        self.e8 = Entry(frame, textvariable=self.phone_var)
        self.e8.grid(row=7, column=1)

        # cell variable and entry
        self.cell_var = StringVar()
        self.e9 = Entry(frame, textvariable=self.cell_var)
        self.e9.grid(row=8, column=1)

        # quit, search, clear, add, delete buttons
        quit_button = Button(btm_frame, text="Quit", relief=GROOVE, command=parent.destroy)
        quit_button.pack(side=RIGHT)        

        search_button = Button(btm_frame, text="Search", relief=GROOVE, command=self.search)
        search_button.pack(side=RIGHT, padx=1, pady=1)

        clear_button = Button(btm_frame, text="Clear", relief=GROOVE, command=self.clear_entries)
        clear_button.pack(side=RIGHT, padx=1, pady=1)        

        del_button = Button(btm_frame, text="Delete", relief=GROOVE, command=self.del_employee)
        del_button.pack(side=RIGHT, padx=1, pady=1)

        add_button = Button(btm_frame, text="Add", relief=GROOVE, command=self.add_data)
        add_button.pack(side=RIGHT, padx=1, pady=1)


    def add_data(self):        
        name = self.name_var.get()
        age = self.age_var.get()        
        addr = self.address_var.get()
        city = self.city_var.get()
        state = self.state_var.get()
        zip = self.zip_var.get()
        ssn = self.ssn_var.get()
        phone = self.phone_var.get()
        cell = self.cell_var.get()
        # create new Employee in .db
        new_person = Employee(name=name, age=age, address=addr, city=city, state=state, zip=zip, ssn=ssn, phone=phone, cell=cell)
        session.add(new_person)
        session.commit()
        session.close()
        self.callback()
        return        

    def callback(self):        
        showinfo("New Employee", "Data Added")
        self.clear_entries()
        return        

    def clear_entries(self):
        entries = [self.e1, self.e2, self.e3, self.e4, self.e5, self.e6, self.e7, self.e8, self.e9]
        for entry in entries:
            entry.delete(0, END)
        return            

    def search(self):
        search_win = Toplevel()
        search_win.title("Employee Search")

        # create labels for each employee attribute
        attr =   ["Id","Name","Age","Address","City","State","Zip","SSN","Cell","Phone"]
        column = 0
        for a in attr:
                Label(search_win, text=a).grid(row=0,column=column,padx=2, pady=2)
                column += 1

        # search all employees, put each emp. in Entry Widget with For Loop
        res = session.query(Employee).all()
        row = 1
        column = 0
        for employee in res:
            txt = [employee.id, employee.name, employee.age, employee.address, employee.city, employee.state, employee.zip, employee.ssn, employee.phone, employee.cell]
            for t in txt:
                ent = Entry(search_win, relief=RIDGE, width=19)
                ent.grid(row=row, column=column, sticky=W, padx=1, pady=1)
                ent.insert(0, t)
                column += 1
            row += 1
            column = 0
        return

    def del_employee(self):
        del_win = Toplevel()
        del_win.title("Delete Employee")

        id_label = Label(del_win, text="Enter Employee Id:")
        id_label.grid(row=0, column=0, padx=5, pady=5)

        self.employee_id = IntVar()
        self.e10 = Entry(del_win, textvariable=self.employee_id)
        self.e10.grid(row=0, column=1, padx=5, pady=5)

        del_button = Button(del_win, text="Delete Employee", relief=GROOVE, command=self.erase)
        del_button.grid(row=0, column=2, padx=5, pady=5)
        return

    def erase(self):
        emp_id = self.employee_id.get()
        res = session.query(Employee).filter(Employee.id==emp_id).first()
        session.delete(res)
        session.commit()
        showinfo("Employee", "Data Deleted")
        return



if __name__ == '__main__':
    root = Tk()
    root.geometry("310x270")
    root.title("Employee Info")
    mygui = GUI(root)
    root.mainloop()

然而，当我这样做时，它产生了一个问题，因为

age

现在变成了一个局部变量（正如回溯在另一篇文章中指出的），并且我得到了UnboundLocalError：在赋值之前引用的局部变量'age'。我尝试通过分离数据的检索和添加到数据库来更改代码，如下所示

def get_data(self):        
    self.name = self.name_var.get()
    try:
        self.age = self.age_var.get()
    except ValueError:
        showinfo("Error:", "Please Enter A Number In Age Field.")
    self.addr = self.address_var.get()
    self.city = self.city_var.get()
    self.state = self.state_var.get()
    self.zip = self.zip_var.get()   
    self.ssn = self.ssn_var.get()
    self.phone = self.phone_var.get()
    self.cell = self.cell_var.get()

def add_data(self):
    self.get_data()
    # create new Employee in .db
    new_person = Employee(name=self.name, age=self.age, address=self.addr, city=self.city, state=self.state, zip=self.zip, ssn=self.ssn, phone=self.phone, cell=self.cell)
    session.add(new_person)
    session.commit()
    session.close()
    self.callback()
    return

然而，我有一个不同的伪装相同的问题。现在我得到了

AttributeError:GUI实例没有属性“age”

。我不知道如何避开这些问题。我尝试在try/except子句

self.age=0

之前向age添加一个默认值，这确实纠正了错误，但又产生了另一个问题。如果用户输入的是字符串而不是int，则showinfo框将显示警告，但当用户单击“确定”时，默认值“0”将自动添加到数据库中，而不是给用户再次输入年龄数字的机会。当然，我可以在类Employee中将年龄字段更改为字符串，但这不是我想要的。我不知道该怎么办。非常感谢您的帮助！不管怎样，这是原始代码

try:
        self.age = self.age_var.get()
    except ValueError:
        showinfo("Error:", "Please Enter A Number In Age Field.")

from datetime import datetime
from Tkinter import *
from tkMessageBox import *
import sqlite3, sqlalchemy
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, DateTime, Integer, String, MetaData
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker

# map classes to tables through Base Class
Base = declarative_base()


class Employee(Base):
    __tablename__ = 'employee'
    id = Column(Integer, primary_key=True)
    name = Column(String(250))
    age = Column(Integer)
    address = Column(String(250))
    city = Column(String(10))
    state = Column(String(2))
    zip = Column(Integer)
    ssn = Column(String(12))
    phone = Column(String(12))
    cell = Column(String(12))

# create engine for Session connection
engine = create_engine('sqlite:///employee.db')

# create all tables in engine ('CREATE TABLE' in raw SQL)
Base.metadata.create_all(engine)

# create configured 'Session' class
Session = sessionmaker(bind=engine)

# create session
session = Session()


class GUI:
    def __init__(self, parent):
        self.parent = parent

        # create top frame
        frame = Frame(parent)
        frame.pack(expand=YES, fill=BOTH, padx=5, pady=5)

        # create bottom frame
        btm_frame = Frame(parent, relief=SUNKEN, borderwidth=1)
        btm_frame.pack(side=BOTTOM, expand=YES, fill=BOTH, padx=5, pady=5)

        # create datetime object
        d = datetime.today()
        date = d.strftime("%Y-%m-%d")


#------------------------Create Labels-------------------------------#


        # label to display date
        date_label = Label(btm_frame, text=date)
        date_label.pack(side=LEFT)

        # name label
        name_label = Label(frame, text="Enter Name:")
        name_label.grid(row=0, sticky=W)

        # age label
        age_label = Label(frame, text="Enter Age:")
        age_label.grid(row=1, sticky=W)

        # address label
        addr_label = Label(frame, text="Enter Address:")
        addr_label.grid(row=2, sticky=W)

        # city label
        city_label = Label(frame, text="Enter City:")
        city_label.grid(row=3, sticky=W)

        # state label
        state_label = Label(frame, text="Enter State:")
        state_label.grid(row=4, sticky=W)

        # zip code label
        zip_label = Label(frame, text="Enter Zip Code:")
        zip_label.grid(row=5, sticky=W)

        # ssn label
        ssn_label = Label(frame, text="Enter Social Security #:")
        ssn_label.grid(row=6, sticky=W)

        # phone label
        phone_label = Label(frame, text="Enter Phone #:")
        phone_label.grid(row=7, sticky=W)

        # cell label
        cell_label = Label(frame, text="Enter Cell #:")
        cell_label.grid(row=8, sticky=W)


#----------------------Create Vars and Entry-------------------------#


        # name variable and entry
        self.name_var = StringVar()
        self.e1 = Entry(frame, textvariable=self.name_var)
        self.e1.grid(row=0, column=1)

        # age variable and entry
        self.age_var =  IntVar()
        self.e2 = Entry(frame, textvariable=self.age_var)
        self.e2.grid(row=1, column=1)

        # address variable and entry
        self.address_var = StringVar()
        self.e3 = Entry(frame, textvariable=self.address_var)
        self.e3.grid(row=2, column=1)

        # city variable and entry
        self.city_var = StringVar()
        self.e4 = Entry(frame, textvariable=self.city_var)
       self.e4.insert(0, "Roanoke")        # insert default value
       self.e4.grid(row=3, column=1)

        # state variable and entry
        self.state_var = StringVar()
        self.e5 = Entry(frame, textvariable=self.state_var)
        self.e5.insert(0, "VA")             # insert default value
        self.e5.grid(row=4, column=1)

        # zip code variable and entry
        self.zip_var = IntVar()
        self.e6 = Entry(frame, textvariable=self.zip_var)
        self.e6.grid(row=5, column=1)

        # s.s.n variable and entry
        self.ssn_var = StringVar()
        self.e7 = Entry(frame, textvariable=self.ssn_var)
        self.e7.grid(row=6, column=1)

    # phone variable and entry
        self.phone_var = StringVar()
        self.e8 = Entry(frame, textvariable=self.phone_var)
        self.e8.grid(row=7, column=1)

        # cell variable and entry
        self.cell_var = StringVar()
        self.e9 = Entry(frame, textvariable=self.cell_var)
        self.e9.grid(row=8, column=1)

        # quit, search, clear, add, delete buttons
        quit_button = Button(btm_frame, text="Quit", relief=GROOVE, command=parent.destroy)
        quit_button.pack(side=RIGHT)        

        search_button = Button(btm_frame, text="Search", relief=GROOVE, command=self.search)
        search_button.pack(side=RIGHT, padx=1, pady=1)

        clear_button = Button(btm_frame, text="Clear", relief=GROOVE, command=self.clear_entries)
        clear_button.pack(side=RIGHT, padx=1, pady=1)        

        del_button = Button(btm_frame, text="Delete", relief=GROOVE, command=self.del_employee)
        del_button.pack(side=RIGHT, padx=1, pady=1)

        add_button = Button(btm_frame, text="Add", relief=GROOVE, command=self.add_data)
        add_button.pack(side=RIGHT, padx=1, pady=1)


    def add_data(self):        
        name = self.name_var.get()
        age = self.age_var.get()        
        addr = self.address_var.get()
        city = self.city_var.get()
        state = self.state_var.get()
        zip = self.zip_var.get()
        ssn = self.ssn_var.get()
        phone = self.phone_var.get()
        cell = self.cell_var.get()
        # create new Employee in .db
        new_person = Employee(name=name, age=age, address=addr, city=city, state=state, zip=zip, ssn=ssn, phone=phone, cell=cell)
        session.add(new_person)
        session.commit()
        session.close()
        self.callback()
        return        

    def callback(self):        
        showinfo("New Employee", "Data Added")
        self.clear_entries()
        return        

    def clear_entries(self):
        entries = [self.e1, self.e2, self.e3, self.e4, self.e5, self.e6, self.e7, self.e8, self.e9]
        for entry in entries:
            entry.delete(0, END)
        return            

    def search(self):
        search_win = Toplevel()
        search_win.title("Employee Search")

        # create labels for each employee attribute
        attr =   ["Id","Name","Age","Address","City","State","Zip","SSN","Cell","Phone"]
        column = 0
        for a in attr:
                Label(search_win, text=a).grid(row=0,column=column,padx=2, pady=2)
                column += 1

        # search all employees, put each emp. in Entry Widget with For Loop
        res = session.query(Employee).all()
        row = 1
        column = 0
        for employee in res:
            txt = [employee.id, employee.name, employee.age, employee.address, employee.city, employee.state, employee.zip, employee.ssn, employee.phone, employee.cell]
            for t in txt:
                ent = Entry(search_win, relief=RIDGE, width=19)
                ent.grid(row=row, column=column, sticky=W, padx=1, pady=1)
                ent.insert(0, t)
                column += 1
            row += 1
            column = 0
        return

    def del_employee(self):
        del_win = Toplevel()
        del_win.title("Delete Employee")

        id_label = Label(del_win, text="Enter Employee Id:")
        id_label.grid(row=0, column=0, padx=5, pady=5)

        self.employee_id = IntVar()
        self.e10 = Entry(del_win, textvariable=self.employee_id)
        self.e10.grid(row=0, column=1, padx=5, pady=5)

        del_button = Button(del_win, text="Delete Employee", relief=GROOVE, command=self.erase)
        del_button.grid(row=0, column=2, padx=5, pady=5)
        return

    def erase(self):
        emp_id = self.employee_id.get()
        res = session.query(Employee).filter(Employee.id==emp_id).first()
        session.delete(res)
        session.commit()
        showinfo("Employee", "Data Deleted")
        return



if __name__ == '__main__':
    root = Tk()
    root.geometry("310x270")
    root.title("Employee Info")
    mygui = GUI(root)
    root.mainloop()

这是我在更改上面的代码后遇到的第一个错误，在add_data方法中将try:except子句添加到age变量中。换句话说，将上面的“添加数据”方法更改为：

def add_data(self):        
    name = self.name_var.get()
    try:
        age = self.age_var.get()
    except ValueError:
        showinfo("Error:", "Please Enter A Number In Age Field.")
    addr = self.address_var.get()
    city = self.city_var.get()
    state = self.state_var.get()
    zip = self.zip_var.get()   
    ssn = self.ssn_var.get()
    phone = self.phone_var.get()
    cell = self.cell_var.get()
    # create new Employee in .db
    new_person = Employee(name=name, age=age, address=addr, city=city, state=state, zip=zip, ssn=ssn, phone=phone, cell=cell)
    session.add(new_person)
    session.commit()
    session.close()
    self.callback()
    return

当用户在年龄字段中输入字符串，然后单击showinfo对话框中的“确定”时，我会出现此错误）：

---

在问题的开头有一块代码，后面跟着“

age

现在成为局部变量”。这是不可能的，因为a）您显示的代码既不设置也不使用名为

age

的变量，b）try不这样做。您的代码设置了

self.age

，但这与名为

age

的局部变量完全不同

错误消息将告诉您所有需要知道的信息。如果它说“赋值前引用的局部变量‘age’”，那么你可以相信它说的是字面上的事实。你必须扪心自问：“为什么当我认为年龄是全球性的时候，

age

（而不是

self.age

）是本地的？”，或者“为什么当我认为年龄是全球性的时候，

age

没有设置？”。try语句本身不会神奇地使变量成为局部变量

让我重复最后一行：try语句本身不会神奇地使变量成为局部变量。你在评论中链接到的另一个答案给了你不好的建议

理解正在发生的事情的一个简单的低技术方法是，在分配局部变量

age

之后放置一个print语句，您将看到该行代码没有被执行。你需要逐步了解你的逻辑，看看为什么它没有被执行

如果真正的问题是它在抱怨一个局部变量

age

，而您正在设置一个名为

self.age

的属性，那就是问题所在--将

age

更改为

self.age

，然后再次，在设置

self.age

的地方放一条print语句，以在出现错误之前向自己证明它是或不是被设置的

不幸的是，你把问题搞得一团糟。我认为代码有两个不同的版本，一条错误消息与“原始版本”一起出现，而当前版本没有错误。我想。这真的很难理解

---

可能问题很简单，如果您的

try

在设置变量时捕捉到错误，那么该变量将无法设置。如果在try之后有其他代码并使用该变量，则会失败，因为

try

块未能设置该变量。一个简单的解决方案可能是在

catch

块中将变量设置为零

你是说你认为年龄是一个局部变量吗？如果是这样，那就不是真的。您能告诉我们实际的错误和堆栈跟踪吗？我建议更仔细地阅读您的错误消息——它们确切地告诉您问题所在。错误“GUI实例没有属性年龄”是正确的：您的GUI类没有属性

age

。为什么你认为它有或者应该有？为什么我认为它有一个年龄变量？在add\u data方法中没有看到代码

age=self.age\u var.get（）

？更不用说脚本（没有try:except）工作得非常完美。只有在我添加了try之后，我才发现了错误。下面是完整的错误：Tkinter回调回溯中的异常（最近一次调用最后一次）：文件“C:\Python27\lib\lib tk\Tkinter.py”，第1532行，在调用返回self.func（*args）文件“C:/Python27/test3 gui.py”，第185行，在添加数据new\u person=Employee中（name=self.name，age=self.age，address=self.addr，city=self.city，state=self.state，zip=self.zip，ssn=self.ssn，phone=self.phone，cell=self.cell）AttributeError:GUI实例没有属性'age'，如果我运行原始代码（如上）将add_data方法更改为

try:age=self.age\var.get（）除了ValueError:showinfo（“Error:，”请在年龄字段中输入一个数字。”）

我得到了这个错误…Tkinter回调回溯中出现异常（最近一次调用）：调用返回self.func（*args）文件“C:\Python27\test2\u gui.py”中的第1532行文件“C:\Python27\lib tk\Tkinter.py”，第182行，在add_data new_person=Employee（姓名=姓名，年龄=年龄，地址=地址，城市=城市，州=州，邮编=邮编，ssn=ssn，电话=电话，手机=手机）中取消绑定LocalError:lo