Finish Building A Simple Calculator App - Python Tkinter GUI Tutorial #7 

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Learning so much. Your down to earth manner ( including non editing out of occasional mistakes ) and good humour makes it all the more enjoyable. So big thanks!

I took this calculator making as a challenge. And before watching you, I successfully made it. I grabbed the input as a string using get(). Like "2+6*7" or whatever.. and then using eval(), I calculated the result. That was a little smart calculator 😊... All Thanks To Your Lovely Tutorials.

Man you are insane!!!! Hey , can you believe it I developed my own GUI calculator.!!!

Thank you for providing such videos for 'free'. Loved how you taught us to build the fully functional calculator! But there is are some problems that you might face while using the calculator. You can't perform calculations on floats. And if you divide something by zero it will give you an error. This is how you can solve both of these problems- 1. Just change int into float. 2. You can put the divide function into a try block and perform exception handing on it. Hope this helped you

I tired smashing the like button but ended up breaking my laptop screen. Now I can't code anything. Joking aside, loved the super helpful tutorial!

John, wanted to say ... keep up the good work. Short, sweet, simple ... always a winning formula. This is my first Python GUI effort and I'm glad I took a look. I can already see how to build some simple apps for "admin" type tasks. I haven't looked ahead, but I'm hoping you show us how to package this up for distro. I'm a data engineer so my GUI dev skills are a bit weak. In any case, thanks.

Hey thank you for such helpful and earnest videos. You've been of great assistance in starting to build my logic in using the tkinter module

Thanks ...all makes sense ..no classes ..great.Easy conversion for Python 2 or 3

great tutorials...but for this one i have a question..cant we define global variable math once and use it thorughout in various functions?

Best video course on python. super easy to follow and understand

Olá, sou Brasileiro, estou começando na linguagem Python, estou gostando muito da sua didática, quero aprender mais, parabéns.

Great explanation and gave me a few ideas for my own applications. I would suggest, though, that all the repeated code within the button_add, button_subtract, etc. functions be merged into another function to avoid duplication. All you need to do is set the global math in each of them and then hand off to the common function. Thanks for your efforts in explaining Python.

Hi Sir, your work is great and specifically this course is very good and i have been learning tkinter here only. There is a suggestion that you might want to entertain: if you would stay more confident and less doubtful in your codes, that would lead to the students also being confident in your work. Thank You

you are the best teacher in the world

great tutorials, now am trying to execute all your tkinter projects and i had some issues with the int(f_number) whenever the answer is converted to a float. i decided to use float instead and it works well.. Thanks ones again.

im chain whatching this tutorial. Its amazing. Thank you for your help

Now that's what I call a quality work! Thank you so much, John, I am very new to your channel, but I am enjoying it so much! Already learnt a lot of stuff about GUI through your videos, and I have just started! Keep up the good job, sir! P.S. I was also wondering if there is a way to store a previous operation in a memory by means of consecutive "+" button clicking or smth similar (without clicking "=")? Say for example, I type 2, then +, then 3, then again +, then 4: so that I could get 9 instead of 7. I am not that good with algorythms, however I am learning. Thank you in advance, John!

Beautifully explained. Learning and enjoying alot! Thanks!

Very nice video keep up the good work . I have a question however . How to subtract or divide or... many numbers ? Like 1+4+8+4 without clicking equal button . Any suggestion ?

Before you I watched this video, I attempted to accomplish this via my own problem solving skills. I literally attempted the exact same strategy, except instead of using a string variable, I used a boolean, so instead of math='addition', I did addition=True. I cant wrap my head around why it wont work, I'm sure there is something weird going on under the hood. Did I possibly just code something wrong using this strategy? or if you try this exact same method using Booleans, it causes some type of error?

Hello from Croatia - 🇭🇷 First, I just want to say that I love your videos. I think that your explaining skills are a great. Second - I have a question : I built my calculator and everything works perfect but I want to know how the Entry widget recognizes "123" as one number and not as three numbers - "1" , "2" , "3". Is that just how it works or what ? Because we don't need to code anything for it to do that.

Awesome tutorial!! Thank you for being so helpful. I finally got it all hatched out.

Like button smashed and subscribed. - What a great tutorial!

Great tutorial! It really helped a lot, especially since I'm an absolute beginner. I noticed a small problem: if the user clicks the equal button before doing anything else the program gives an error since we haven't defined this eventuality in the button_equal function and it doesn't recognize the variable 'math'. I solved this by creating another global variable called 'math' at the very first lines of the whole program and gave it the value 0 (it could be any value) so that, if the equal button is pressed with no reason nothing happens and the program doesn't crash. I know there wouldn't be any reason to just randomly click the equal button but it still is a possibily that the users does that so I figured this is a good way to prevent everything from crashing :)

Thank you for your video... I literally have a school project I need to submit tomorrow and your video has helped a lot. Thanks💚 I also smashed the like button :)

Totally binge watching these right now. Please don't tell everyone how much of a nerd I am...

I finally made it but i want to know how to color buttons when we click on them and when they are not clicked also how to color the text please make a video if you haven't or please share the link of video if you've made because its very difficult to find a video from a group of 202 videos. Thank you

Your coding videos are simply the best! But I have one question: is it possible to place a button for two rows (vertically)? I'm trying to put an exit button vertically, like for both rows 5 and 6, for the column 0, but it doesn't work? There are buttons on both rows 5 and 6 and on columns 1 and 2. (sorry for the confusing explanation)

can you please tell me what happens in the following lines: def button_click(number): current = e.get() e.delete(0, END) e.insert(0, str(current) + str(number)) My thinking is when I press the number 5 it will store it in "current" variable then insert str(current) + str(number) . Here both current, number has the same indentity (i.e. 5) . So shouldnt we get 55 by pressing the button once?

You are simply great...

I was wondering if its right to have the same identifier for both a button object and a function e.g button_equal = Button(...), also def button_equal(): .... You have the same thing for button_add, button_subtract etc.

just made a calculator thanks sir !!

Hi Dear John.İn this calculator result for example 10/2+6 or 21*2+5 not correctly.Please give me answer:)Thanks

Gracias profe, excelente trabajo.

Hi John I have been playing around with creation of buttons and trying to insert new functions, but failed in the Square Root thing HAHA. I - from math import * and the .sqrt functions seems to be fine to use. however I can't make it work. any tips ? I appreciate your work. I have been learning alot. thanks

Is there any way to input decimal digits in this calculator?

Thanks man , this is the first app i've ever built thanks to you. One Subcriber more!!

Hello John..... I tried to edit the calculator...and after that in the main output, All the buttons are faraway from each other: Code: from tkinter import * root = Tk() root.title('CALC') e=Entry(root, font=('arial',20,'bold'), width=35, borderwidth=30 , insertwidth=4, bg='powder blue', justify='right') e.grid(columnspan=4) def button_clk(number): # e.delete(0, END) current = e.get() e.delete(0, END) e.insert(0,str(current)+str(number)) def button_clear(): e.delete(0, END) def button_add(): first_number=e.get() global f_num global math math="addition" f_num = int(first_number) e.delete(0, END) def button_equal(): second_number=e.get() e.delete(0,END) if math =="addition": e.insert(0, f_num + int(second_number)) if math =="subtraction": e.insert(0, f_num - int(second_number)) if math =="multiplication": e.insert(0, f_num * int(second_number)) if math =="division": e.insert(0, f_num / int(second_number)) def button_subtract(): first_number = e.get() global f_num global math math = "subtraction" f_num = int(first_number) e.delete(0, END) def button_multiply(): first_number = e.get() global f_num global math math = "multiplication" f_num = int(first_number) e.delete(0, END) def button_divide(): first_number = e.get() global f_num global math math = "division" f_num = int(first_number) e.delete(0, END) #Define the buttons button_1 = Button(root, text="1",font=('arial',20,'bold'),bd=8, fg='black', bg='powder blue',padx=16,pady=16,command=lambda:button_clk(1)) button_2 = Button(root, text="2",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=lambda:button_clk(2)) button_3 = Button(root, text="3",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=lambda:button_clk(3)) button_4 = Button(root, text="4",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=lambda:button_clk(4)) button_5 = Button(root, text="5",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=lambda:button_clk(5)) button_6 = Button(root, text="6",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=lambda:button_clk(6)) button_7 = Button(root, text="7",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=lambda:button_clk(7)) button_8 = Button(root, text="8",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=lambda:button_clk(8)) button_9 = Button(root, text="9",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=lambda:button_clk(9)) button_0 = Button(root, text="0",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=lambda:button_clk(0)) button_add= Button(root, text="+",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=button_add) button_equal = Button(root, text="=",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=button_equal) button_clear = Button(root, text="C",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=button_clear) button_subtract= Button(root, text="-",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=button_subtract) button_multiply= Button(root, text="x",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=button_multiply) button_divide= Button(root, text="/",font=('arial',20,'bold'),bd=8,fg='black',bg='powder blue',padx=16,pady=16,command=button_divide) #Put the buttons on the screen button_1.grid(row= 3, column=0) button_2.grid(row= 3, column=1) button_3.grid(row= 3, column=2) button_multiply.grid(row=3,column=3) button_4.grid(row= 2, column=0) button_5.grid(row= 2, column=1) button_6.grid(row= 2, column=2) button_subtract.grid(row=2, column=3) button_7.grid(row=1 , column=0) button_8.grid(row=1 , column=1) button_9.grid(row=1 , column=2) button_add.grid(row=1,column=3) button_0.grid(row=4, column=0) button_clear.grid(row=4,column=1) button_equal.grid(row=4,column=2) button_divide.grid(row=4,column=3) root.mainloop()

sir you are awesome your tutorials are sooo good.

Thank you so much for this tutorial it taught me a lot

Hey man. Been trying to create an Ans button like on Casio scientific calculators where any time you press '=', you store the value in an Answer variable that can be recalled by the button. How would I port it over to another function?

thanks man, that was great but there is only one problem, when I for example add 2 + 3 it equals 5 and that's nice, but when the process is done and i kept pressing the equal button it will keep adding numbers by itself. will be grateful if you told me why is that and how to fix it

when i try to run the program it keeps saying first_number is not defined. I don't know what I'm doing wrong here

Hi I've been following this with a few experiments from my side as well. I was trying to make another class which inherited the existing button class. The intention was you have certain common settings for all the buttons. I was thinking of click function as well in the class which would take the text of the button and put it in the entry box. Could you please tell what could be the syntax for the command. I tried putting (self).click, as mentioned in some link. But it doesn't seem to work. I would have to pass the word self to the function click in order to make it work which is not accepted as "self" isn't getting recognised.

Hi, i suggest use eval function for less the code. Thanks for you teach me

How can I make the calculator in a way where after you click equals, the first thing you type in AFTER that removes the answer to the previous problem, instead of always having to click clear afterwards?

thanks dude for the lesson dude! but i got a problem with the math variable, it prevent me from using function from math directory. maybe i should change that with another word

Thanks for the tutorial. I would like to ask a question. Instead of using the (global f_num and global math) as a global variable inside each function, why can't we have this outside the function? because it is a global variable right ? just had this doubt. pls, clarify me. It would be great.

the tutorial is greater than great!

How should I define point button for example if I want to write 5.25 * 70.56789 ?

Thanks for the tutorial. It was great.

Can I ask you a question? I want to make square root button work, but every time when I make a function and when I press the button, it doesn't work. Can you tell me why?

Do we have any GitHub repo link to see the code ?

Thanks a lot!!, I've successfully made it

Can we add Circle buttons instead of Square ?

watch this with 2x speed , still you can understand. cool and fast !

this video helped me a lot, thank you sir.

മച്ചാൻ പൊളി 😍

How do i add comma's in the input like a extra button ',' and make it work?

Hello Codemy, with this code i don't understand why it it is duplicating my answer eg if I say 2+3 answer is supposed to be 5 but mine is saying 55.Please assist me or anyone who knows what my problem is?

I did exactly same coding with yours. But I keep getting this error [AttributeError: 'Button' object has no attribute 'gird'] I did googling but I can't figure out what is problem. Can you help me?

For some reason my program registers when I want to add numbers, but it doesn't register the other operations (* / -) and just deletes whatever is in the data entry box.

When I tried to add, subtract, divide, or multiply the answer from a division answer that was a decimal, I would get an error. I changed all the int to float and now its all fine.

Sir I need a code to add factorial button in calculator... Plzz help... I tried so many times

Does anyone happen to know why *global f_num* and *global math* are returning *is not defined in the global scope* errors? I followed the tutorial step-by-step but always end up with the same error. FYSA: My calculator works with the errors, but don't know why.

Please help me sir!!! I made calculator of my own but when i am using int with get() as you have done, then i am getting the following error invalid literal for int with base 10 but your works fine with it.. Please help

I have a problem with this line it stile say to me something wrong in this line Button_1=Button(root, text="1", padx=40, pady=20, command=Lambda: Button_click(1))

nice explaination

Thank You So Much!!!

Great work buddy

I am really grateful for this tutorial but it could have been easier

3 test cases were not passing like 2+3+4= it fails and if we click2+ and then hit clear the enter 3= it gives 5 and 2= also fails !! can anyone suggest how to rectify those

The internal command PhotoImage works fine for me using png file. I cound not compile with PIL using pyinstaller, so I tried PhotoImage.

Hai!! i am getting error near def button_substract(): return. What to do to rectify?

simply AWESOME:)

hello i just wanted to say that i followed the steps step by step but when i finished it says that f_num is not defined please Help

hey can anyone help me with printing exceptions the entry widget...like when u divide by zero,u get nothing so i wanna print out cannot divide by zero....any ideas how??

stupendous!!

My program isnt working right, the subtract button isnt showing up?

And how can we do when we divide a number by zero?

you are so good

Getting confused, how did the calculator know that it needs to multiply or divide? The global variable math is only been given a string which "substract" etc...

Thank you

Hi i want to make this calculator ready for use to user , when he need to use this calculator i want him just clique on a file or something and this calculator show up

Thanksss😍♥

Thanks man

how to make numbers appear on right side like as in real calculators ?

While running the code , The columns are showing gap in between eachother

awesome!

Pycharm shows error=5 nd no interpreter found any solution to solve the error

great model, but i am confused on adding functions like square root in this program

one thing i noticed is you keep repeating code like cant we inherit and use functions such as eval() instead the if statement

if math == "addition" SyntaxError: invalid syntax What should I do?

Why don't you use an IDE instead of using both text editor and terminal

Where can have this source code ??

great tutorials

it would be better if you have used "eval" function but i was the best tutorial

$ python calculator.py File "calculator.py", line 32 e.insert(0, f_num + int(second_number)) ^ TabError: inconsistent use of tabs and spaces in indentation Please Fix This Error John Elder

nice..