Python Tkinter attribute error entry in random letter typing test

command= expect only function name - without () and parameters.

Using command=self.usertypetest(0) you run self.usertypetest(0)
and its result is assigned to command=.

But self.usertypetest(0) use self.entry which wasn't defined yet.

self.entry is defined after Tkinter.Button(...command=self.usertypetest(0)...)

If you need to assing function with parameters then use lambda

command=lambda:self.usertypetest(0)

And now it works.

EDIT:

Full working version:

(I changed some variable names)

import Tkinterimport randomclass simpleapp_tk(Tkinter.Tk):    def __init__(self,parent):        Tkinter.Tk.__init__(self,parent)        self.parent = parent        self.initialize()        self.started = False # True when timer is running    def initialize(self):        self.grid()        self.infoVariable = Tkinter.StringVar()        self.labelInfo = Tkinter.Label(self, textvariable=self.infoVariable, anchor="w", fg="blue", bg="gold")        self.labelInfo.grid(column=0, row=0, sticky='EW')        self.infoVariable.set(u"Press button to begin!")        self.buttonStart = Tkinter.Button(self, text=u"Start", command=self.on_buttonStart, fg="black", bg="green")        self.buttonStart.grid(column=2, row=0)        self.timeVariable = Tkinter.StringVar()        self.labelTime = Tkinter.Label(self, textvariable=self.timeVariable, anchor="w", fg="blue", bg="gold")        self.labelTime.grid(column=1, row=0, sticky='EW')        self.timeVariable.set(u'Time')        self.entryVariable = Tkinter.StringVar()        self.entry = Tkinter.Entry(self, textvariable=self.entryVariable, fg="black", bg="white")        self.entry.grid(column=0, row=1, columnspan=2, sticky='EW')        self.entryVariable.set(u"")        self.entry.bind('<Key>', self.on_key) # event        self.grid_columnconfigure(0,weight=1)        self.grid_rowconfigure(0,weight=1)        self.resizable(True,True)    def on_buttonStart(self):        if not self.started:            # reset values            self.started = True            self.number_of_letters = 20            self.score = 0            self.time = 0.0            # select first letter            self.randletter = random.choice('qwer')            # show first letter and score            self.infoVariable.set('Score:' + str(self.score)+' | Press ' + self.randletter)            # start timer            self.after(100, self.timer)    def on_key(self, event):        if not self.started:            self.entryVariable.set('')        else:            if event.char == self.randletter:                print 'Correct', event.char                self.score += 5            else:                print 'Incorrect', event.char                self.score -= 2            self.number_of_letters -= 1            if self.number_of_letters == 0:                self.started = False                self.entryVariable.set('')                self.infoVariable.set('Score:' + str(self.score))            else:                self.randletter = random.choice('qwer')                self.infoVariable.set('Score:' + str(self.score)+' | Press ' + self.randletter)    def timer(self):        if self.started:            self.time += .1            self.timeVariable.set('Time: ' + str(round(self.time,1)) )            self.after(100, self.timer)if __name__ == "__main__":    app = simpleapp_tk(None)    app.title('LoL Practice')    app.geometry("700x50")    app.configure(background='black')    app.mainloop()