Question

我是python中的绝对初学者，我试图理解为什么最后一行不起作用。 PyCharm声明＆＃34; n＆＃34;是一个未解决的引用，我已确保该函数返回字符串输入。线本身或函数是一个问题吗？

def askforname():
    n = str(input("Please enter your name: "))
    return n


def printchoice():
    print("You are starving and go down to the kitchen.")
    print("You are now confronted with an eon defining choice, spaghetti or lasagna")


def hello(n):
    print("Hello " + n + "!")


def choiceone():
    choicelasagna = str(input("Type \"Lasagna\" to pick lasagna and type \"Spaghetti\" to pick spaghetti: "))
    return choicelasagna


def kalle():
   ch = choiceone()
   if ch == "Lasagna" or "lasagna":
      print("You cooked some warm lasagna and enjoyed it")
else:
    print("You cooked some spaghetti and enjoyed it")


def main():
    n = askforname()
    hello(n)
    printchoice()
    kalle()


def goodbye(n):
    print("Goodbye" + n)


def request():
    print("")


main()
goodbye(n)

Answer 1

n仅在函数main中定义。要在n之外访问main，您需要从main

返回

def main():
    n = askforname()
    hello(n)
    printchoice()
    kalle()
    return n

n = main()

并捕获返回的值：

然后，您可以根据需要访问print(n)：

Private Sub Command95_Click()
DoCmd.TransferSpreadsheet acExport, acSpreadsheetTypeExcel9, "Sheet1", CurrentProject.Path & "\PR1.xls", False, A3
DoCmd.TransferSpreadsheet acExport, acSpreadsheetTypeExcel9, "Performance_report_HW_H1story", CurrentProject.Path & "\Performance report HW.xls", False, A3

'Change format in Excel cells
'Dim exApp As Excel.Application
'    Dim exBook As Excel.Workbook
'    Dim exSheet As Excel.Worksheet
'    Dim BookName As String

'Set exApp = New Excel.Application
'BookName = CurrentProject.Path & "\Performance report HW.xls"

'Set exBook = exApp.Workbooks.Open(BookName)

'Set exSheet = exBook.Worksheets(1)

'exSheet.Activate

'exSheet.Range("A3", "AQ30000").Font.Size = 8
'exSheet.Range("A3", "AQ30000").Font.Name = "Arial"
'exSheet.Range("l3", "l30000").NumberFormat = "hh:mm"
'exSheet.Range("o3", "o30000").NumberFormat = "hh:mm"

'Set exSheet1 = exBook.Worksheets(2)

'exSheet.Activate

'exSheet1.Range("A3", "AQ30000").Font.Size = 8
'exSheet.Range("A3", "AQ30000").Font.Name = "Arial"
'exSheet.Range("l3", "l30000").NumberFormat = "hh:mm"
'exSheet.Range("o3", "o30000").NumberFormat = "hh:mm"


'exBook.Save

'exApp.Interactive = True
'    exBook.Close
'    Set exSheet = Nothing
'    Set exBook = Nothing
'    Set exApp = Nothing

MsgBox "File stored in " & CurrentProject.Path & "\Performance report HW.xls", vbDefaultButton1
DoCmd.SetWarnings True
End Sub

Answer 2

您的代码存在的问题是，您要将变量n传递给goodbye(n)函数而不先定义n。由于名称n未指向任何值，因此它是未解决的引用。

在n中定义main()并不会使main()以外的功能可以访问它。这样的规则称为范围规则。变量的范围是可以自由访问的代码区域，包括定义它的区域。

在这种情况下，n的范围仅限于main()功能。这意味着n以外的功能无法使用main();因此n未定义，您无法将其（不存在）值传递给另一个函数。

您可以在 n之外定义main() ，以使其可供其他功能使用：

... def main(): hello(n) # here n references a global variable printchoice() kalle() ... # n is defined globally outside main() n = askforname() main() goodbye(n)

Answer 3

问题是那个再见（n）不知道什么＆＃39; n＆＃39;是，As＆＃39; n＆＃39;是main（）函数的局部变量，其范围仅限于Main。其他函数无法识别此变量，因为其范围不是全局的。它是main（）的局部变量。要访问＆＃39; n＆＃39;在其他函数中，您可以在调用main（）函数之前在全局声明它，与其他函数分离。

#To Change Global Variable In Funtions Add Global Before The Variable 
def askforname():
    global n = str(input("Please enter your name: "))
    return n

Python打印未解决的参考文献

3 个答案: