如何修复python中的错误：名称错误：名称未定义

Question

当我键入以下代码并运行程序以使用hostEntry2.get()获取条目中的文本时，它将显示

  

NameError：名称hostEntry2未定义。

我试图删除for循环（然后它可以工作），但是使用下面的代码将不起作用。
我希望应该显示在输入框中输入的文本。

from tkinter import *
host1 = ""
database1 = ""
user1 = ""

def db():
    window1 = Tk()
    window1.title("GIVE INFORAMATION ABOUT DATABASE")

    F0 = Frame(window1, relief = SUNKEN)
    F0.pack(side = LEFT)

    l1 = ["host", "database", "user"]
    l2 = ["HOST", "DATABASE", "USER"]

    for i in range(len(l1)):
        exec("%s2 = Label(F0, font = ('OpenSansCondensed', 12), text = \"  ENTER THE %s:\", width = 30, anchor = \"w\")"%(l1[i], l2[i]))
        exec("%s2.grid(row = %s, column = 0)"%(l1[i], i))
        exec("%sEntry2 = Entry(F0, font = ('OpenSansCondensed', 12), textvariable = \"\", insertwidth = 4, justify = 'right')"%(l1[i]))
        exec("%sEntry2.grid(row = %s, column = 1)"%(l1[i],i))

    submitBtn = Button(F0, padx = 16, pady = 5, font = ('OpenSansCondensed', 10), width = 8, text = " OK ", command = lambda: [f for f in [submit_for_db(hostEntry2.get(), databaseEntry2.get(), userEntry2.get()), window1.destroy()]])
    submitBtn.grid(row = 4, column = 0)
    window1.mainloop()

def submit_for_db(host_enterred, database_enterred, user_enterred, password_enterred):
    global host1
    global database1
    global user1
    global password1
    host1 = host_enterred
    database1 = database_enterred
    user1 = user_enterred
    password1 = password_enterred

db()

Answer 1

未定义函数#!/usr/bin/python3 # -*- coding: utf-8 -*- import unittest class TestDummy(unittest.TestCase): """A Dummy UnitTesting class.""" def test_failure(self): """Fails on test.""" self.fail(msg="Need a failure") @unittest.skip("Need a Skipper") def test_skipping(self): """Skippes on test.""" pass def test_error(self): """Gives a error on test.""" self.not_a_thing() def test_pass(self): """Need a test that passes.""" pass def warp_test_suite(testcase_class): """Load tests from a specific set of TestCase classes.""" suite = unittest.TestSuite() tests = unittest.defaultTestLoader.loadTestsFromTestCase(testcase_class) suite.addTest(tests) return suite if __name__ == "__main__": import json # For saving a JSON-file # The test results dictionary, for the JSON. result_value = {"Failures": 0, "Errors": 0, "Skipped": 0, "Test Runs": 0} # Setup and run the Test runner = unittest.TextTestRunner() TextTestResult = runner.run(warp_test_suite(TestDummy)) # Passes the Result result_value["Failures"] += len(TextTestResult.failures) result_value["Errors"] += len(TextTestResult.errors) result_value["Skipped"] += len(TextTestResult.skipped) result_value["Test Runs"] += TextTestResult.testsRun # Save the result to a JSON-file. with open("result_data.json", 'w') as fp: json.dump(result_value, fp, indent=3) ，我不推荐使用submit_for_db函数

Answer 2

这里似乎没有任何理由使用exec。

l2 = ["HOST", "DATABASE", "USER"]

for i, label in enumerate(l2):
    item = Label(F0, font=('OpenSansCondensed', 12), text="  ENTER THE %s:".format(label), width=30, anchor ="w")
    item.grid(row=i, column=0)
    entry = Entry(F0, font=('OpenSansCondensed', 12), textvariable="", insertwidth=4, justify='right')
    entry.grid(row=i, column = 1)
    entries.append(entry)

submitBtn = Button(F0, padx = 16, pady = 5, font = ('OpenSansCondensed', 10), width = 8, text = " OK ", command = lambda: [f for f in [submit_for_db([entry.get() for entry in entries]), window1.destroy()]])
submitBtn.grid(row = 4, column = 0)

（注意，不过我看不到您在哪里使用标签。）