SyntaxError：解析Python计算器时出现意外的EOF [重复]

Question

我在 Python 3 中有一个计算器，但由于某种原因我的代码不起作用。它工作正常，直到我按下“=”按钮来计算我的东西（使用 tkinter 作为 gui）。这是我的代码（很长，很抱歉，这只是我代码的一部分）

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from tkinter import *

from tkinter.ttk import *

    def SMATH():

        #PUT TEXT IN ENTRY FUNCTION

        def puttext(text):
            sm_ent.insert(0,text)
            return

        #CLEAR THE ENTRY FUNCTION

        def cleartext():
            sm_ent.delete(0, END)
            return

        #GET THE OUTCOME FUNCTION

        def Coutcome():
            calc = caltext.get()
            answer = eval(calc)
            sm_ent = Entry(e_frame, textvariable=caltext, text=answer)

        smathW = Tk()
        smathW.title("Simple Math")
        smathW.resizable(0,0)
        smathW.wm_iconbitmap('icon.ico')

        def quitSmath():
            smathW.destroy()

        #ENTRY FRAME
        e_frame = Frame(smathW)
        e_frame.pack()

        #BUTTONS FRAME

        b_frame = Frame(smathW)
        b_frame.pack()

        #ENTRY
        caltext= StringVar()
        sm_ent = Entry(e_frame, textvariable=caltext)
        sm_ent.pack(fill=Y)

        #LABEL

        sm_inf = Label(smathW, text="Here is the Simple Math mode from CalfoWin")
        sm_inf.pack()

        #BUTTON 7

        sm_butt0 = Button(b_frame, text="7", command=lambda: puttext('7'))
        sm_butt0.grid(row=1, column=0)

        #BUTTON 8

        sm_butt1 = Button(b_frame, text="8", command=lambda: puttext('8'))
        sm_butt1.grid(row=1, column=1)

        #BUTTON 9

        sm_butt2 = Button(b_frame, text="9", command=lambda: puttext('9'))
        sm_butt2.grid(row=1, column=2)

        #BUTTON 4

        sm_butt3 = Button(b_frame, text="4", command=lambda: puttext('4'))
        sm_butt3.grid(row=2, column=0)

        #BUTTON 5

        sm_butt4 = Button(b_frame, text="5", command=lambda: puttext('5'))
        sm_butt4.grid(row=2, column=1)

        #BUTTON 6

        sm_butt5 = Button(b_frame, text="6", command=lambda: puttext('6'))
        sm_butt5.grid(row=2, column=2)

        #BUTTON 1

        sm_butt6 = Button(b_frame, text="1", command=lambda: puttext('1'))
        sm_butt6.grid(row=3, column=0)

        #BUTTON 2

        sm_butt7 = Button(b_frame, text="2", command=lambda: puttext('2'))
        sm_butt7.grid(row=3, column=1)

        #BUTTON 3

        sm_butt8 = Button(b_frame, text="3", command=lambda: puttext('3'))
        sm_butt8.grid(row=3, column=2)

        #BUTTON 0
        sm_butt9 = Button(b_frame, text="0", command=lambda: puttext('0'))
        sm_butt9.grid(row=4, column=0)

        #BUTTON KOMMA

        sm_buttKomma = Button(b_frame, text=".", command=lambda: puttext('.'))
        sm_buttKomma.grid(row=4, column=1)

        #BUTTON EQUALSIGN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

        sm_buttEsign = Button(b_frame, text="=", command=Coutcome())
        sm_buttEsign.grid(row=4, column=2)

        #BUTTON ADDITION

        sm_buttPlus = Button(b_frame, text="+", command=lambda: puttext('+'))
        sm_buttPlus.grid(row=2, column=3)

        #BUTTON SUBTRACKTION

        sm_buttMin = Button(b_frame, text="-", command=lambda: puttext('-'))
        sm_buttMin.grid(row=3, column=3)

        #BUTTON DIVISION

        sm_buttDiv = Button(b_frame, text="/", command=lambda: puttext('/'))
        sm_buttDiv.grid(row=3, column=4)

        #BUTTON MULTIPLICATION

        sm_buttMult = Button(b_frame, text='x', command=lambda: puttext('*'))
        sm_buttMult.grid(row=2, column=4)

        #BUTTON CLEAR

        sm_buttClear = Button(b_frame, text="Clear", command=lambda: cleartext())
        sm_buttClear.grid(row=1, column=3)

        #BUTTON QUIT

        sm_buttquit = Button(b_frame, text="Quit", command=lambda: quitSmath())
        sm_buttquit.grid(row=1, column=4)

Answer 1

您使用command = Coutcome() 传递Coutcome 的返回值作为按下按钮时调用的函数。所以现在发生的事情是在创建按钮时调用了Coutcome，而caltext 仍然为空。这意味着您正在运行 eval('')，这会显示您所看到的错误。

这不是您想要的，您希望在按下按钮时调用Coutcome。所以你应该传递函数名，不带括号，作为命令

sm_buttEsign = Button(b_frame, text="=", command=Coutcome)

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对于退出和清除按钮，您应该做同样的事情，去掉括号和 lambda。有时需要使用 lambda 的原因是因为当您必须省略括号时，您无法将变量传递给命令。当您不需要传递变量时，lambda 是多余的。

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此外，您应该小心使用eval。输入错误可以be dangerous。因此，请注意让用户在没有适当限制的情况下向eval 输入内容。