How to fix AttributeError in tkinter program

Question

So I am very new to programming and I'm trying to puzzle out my first tkinter program. It utilizes a formula from thebioneer.com to calculate a person's "Power Level" (think DBZ). However whenever I run it I get "AttributeError: '_tkinter.tkapp' object has no attribute 'entry3' and I can't figure out whats wrong.

import tkinter

class powerapp_tk(tkinter.Tk):
    def __init__(self,parent):
        tkinter.Tk.__init__(self,parent)
        self.parent = parent
        self.initialize()

    def initialize(self):
        self.grid()

        label = tkinter.Label(self, text="Enter Back Squat 1 Rep Max")
        label.grid(column=0,row=0,columnspan=2,sticky='EW')
        entry1 = tkinter.Entry(self)
        entry1.grid(column=0,row=1,sticky='EW')
        label2 = tkinter.Label(self, text="Enter Bench Press 1 Rep Max")
        label2.grid(column=0,row=2,columnspan=2, sticky='EW')
        entry2 = tkinter.Entry(self)
        entry2.grid(column=0,row=3,sticky='EW')
        label3 = tkinter.Label(self, text="Enter Max KM Covered in 12 min")
        label3.grid(column=0,row=4,columnspan=2,sticky='EW')
        entry3 = tkinter.Entry(self)
        entry3.grid(column=0,row=5,sticky='EW')
        label4 = tkinter.Label(self, text="Enter Max Pull Ups With Perfect Form")
        label4.grid(column=0,row=6,columnspan=2,sticky='EW')
        entry4 = tkinter.Entry(self)
        entry4.grid(column=0,row=7,sticky='EW')
        label5 = tkinter.Label(self, text="Enter Standing Vertical Jump in CM")
        label5.grid(column=0,row=8,columnspan=2,sticky='EW')
        entry5 = tkinter.Entry(self)
        entry5.grid(column=0,row=9,sticky='EW')
        label6 = tkinter.Label(self, text="Enter Max One Legged Tennis Ball Catch")
        label6.grid(column=0,row=10,columnspan=2,sticky='EW')
        entry6 = tkinter.Entry(self)
        entry6.grid(column=0,row=11,sticky='EW')
        label7 = tkinter.Label(self, text="Enter IQ Score")
        label7.grid(column=0,row=12,columnspan=2,sticky='EW')
        entry7 = tkinter.Entry(self)
        entry7.grid(column=0,row=13,sticky='EW')
        button = tkinter.Button(self, text=u"Calculate", command=self.calcpower)
        button.grid(column=0,row=14)

        self.grid_columnconfigure(0,weight=2)
        self.minsize(width=400, height=400)
        self.resizable(True, False)
        self.update()
        self.geometry(self.geometry())


    def calcpower(self):
        h = entry3.get() * 100
        i = entry4.get() * 5
        j = entry5.get() * 15
        k = entry6.get() * 8
        l = entry7.get() * 2.5
        powerlevel = int(a)+int(b)+int(h)+int(i)+int(j)+int(k)+int(l)
        print('Your power level is: ' + str(powerlevel))

if __name__=="__main__":
    app = powerapp_tk(None)
    app.title('Power App')
    app.mainloop()

Answer 1

I had to move a few things around and your code has some other issues, but this will get you a little further. Basically the program didnt realize your entry3 was applied to the different functions. Other option would be to declare it as a global but self.entry# is a better solution

import tkinter

class powerapp_tk(tkinter.Tk):
    def __init__(self,parent):
        tkinter.Tk.__init__(self,parent)
        self.parent = parent
        self.initialize()

    def calcpower(self):
        h = self.entry3.get() * 100
        i = self.entry4.get() * 5
        j = self.entry5.get() * 15
        k = self.entry6.get() * 8
        l = float(self.entry7.get()) * 2.5
        powerlevel = int(h) + int(i) + int(j) + int(k) + int(l)
        print('Your power level is: ' + str(powerlevel))

    def initialize(self):

        self.grid()

        label = tkinter.Label(self, text="Enter Back Squat 1 Rep Max")
        label.grid(column=0,row=0,columnspan=2,sticky='EW')
        entry1 = tkinter.Entry(self)
        entry1.grid(column=0,row=1,sticky='EW')
        label2 = tkinter.Label(self, text="Enter Bench Press 1 Rep Max")
        label2.grid(column=0,row=2,columnspan=2, sticky='EW')
        entry2 = tkinter.Entry(self)
        entry2.grid(column=0,row=3,sticky='EW')
        label3 = tkinter.Label(self, text="Enter Max KM Covered in 12 min")
        label3.grid(column=0,row=4,columnspan=2,sticky='EW')
        self.entry3 = tkinter.Entry(self)
        self.entry3.grid(column=0,row=5,sticky='EW')
        label4 = tkinter.Label(self, text="Enter Max Pull Ups With Perfect Form")
        label4.grid(column=0,row=6,columnspan=2,sticky='EW')
        self.entry4 = tkinter.Entry(self)
        self.entry4.grid(column=0,row=7,sticky='EW')
        label5 = tkinter.Label(self, text="Enter Standing Vertical Jump in CM")
        label5.grid(column=0,row=8,columnspan=2,sticky='EW')
        self.entry5 = tkinter.Entry(self)
        self.entry5.grid(column=0,row=9,sticky='EW')
        label6 = tkinter.Label(self, text="Enter Max One Legged Tennis Ball Catch")
        label6.grid(column=0,row=10,columnspan=2,sticky='EW')
        self.entry6 = tkinter.Entry(self)
        self.entry6.grid(column=0,row=11,sticky='EW')
        label7 = tkinter.Label(self, text="Enter IQ Score")
        label7.grid(column=0,row=12,columnspan=2,sticky='EW')
        self.entry7 = tkinter.Entry(self)
        self.entry7.grid(column=0,row=13,sticky='EW')
        button = tkinter.Button(self, text=u"Calculate", command=self.calcpower)
        button.grid(column=0,row=14)

        self.grid_columnconfigure(0,weight=2)
        self.minsize(width=400, height=400)
        self.resizable(True, False)
        self.update()
        self.geometry(self.geometry())


if __name__=="__main__":
    app = powerapp_tk(None)
    app.title('Power App')
    app.mainloop()

Answer 2

Please add self prefix to all your entry fields everywhere. Instead of entry3, use self.entry3.