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I've been following this website for a while. It is really helpful. So, thanks for all the useful tips.

I've been searching for this answer for the past two weeks without any success, so now I'm compelled to ask out of total frustration with my current obstacle.

How do you use StringVar as a list?

Basically, I was coding the following program for my wife. The code is pretty messy as it is my first program I've tried to code.

The idea was that I would take 3 variables; password, secret number and website and then do some work on them using if statements and lists to create a unique password.

First problem was that I couldn't restrict the character length of the entry widgets but in the end i solved that but i still want to limit the characters that can be input.

for instance in the website entry box, i want to allow only letters.

If I could convert StringVar to a list, I could do some work with messy if statements to allow only certain characters in each index but everythime i try it says that stringvars cant be used as a list.

I need them as a list to limit the type of characters that can be entered and also so that i can do work on the variables to get the final output.

CODE:

from Tkinter import *
import Tkinter
from PIL import Image, ImageTk
import os

Title= ("Helvetica", 20, "bold", "underline")
Heading= ("Courier", 20, "bold")
Body= ("Courier", 15)
Body1= ("Courier", 15, "bold")
notice= ("Courier", 10)
Body2= ("Courier", 15, "bold", "underline")

root = Tk()
root.title("Koala Series: Encrypter")
root.configure(background="#ffefd5")
root.geometry('{}x{}'.format(510, 600))

root.columnconfigure(0, weight=1)
root.rowconfigure(0, weight=1) # not needed, this is the default behavior
root.rowconfigure(1, weight=1)
root.rowconfigure(2, weight=1)

website =  StringVar()

Titlemsg = Label(root, text="Koala Encrypter", font=Title, bg="#00FA9A", relief=RAISED,)
Titlemsg.grid( row=7, pady=25, sticky=N+S+E+W)
img1 = ImageTk.PhotoImage(Image.open("koala.jpeg"))
startpic = Label(root, image = img1, relief=RIDGE )
startpic.grid( row=10,pady=25, )
Head = Label(root,anchor=CENTER,text="Welcome to the Koala Encrypter \n\n A Koala series tool that allows you\n\n to Encrypt your passwords \n\n Click \'Start Encrypting\' to continue \n\n", font=Body, bg="#ffefd5", relief=RAISED,)
Head.grid( row=14, pady=25, columnspan=2, sticky=N+S+E+W)

web = Label(root, text="WEBSITE: ", font=Body, bg="#ffefd5", justify=CENTER,)

#website.set("Enter your website here") 
entry = Entry(root,textvariable=website , justify=CENTER,relief=SUNKEN,cursor="pencil", takefocus=True )

Notice1 = Label( text="Please only insert the first 5 letters of the website!!",font=notice, bg="#ffefd5", fg="#0000ff",)

passw = Label(root, text="PASSWORD: ", font=Body, bg="#ffefd5", justify=CENTER)

passwordvar= StringVar()

entry1 = Entry(root, textvariable= passwordvar, justify=CENTER,relief=SUNKEN, cursor="pencil", takefocus=True )

Notice= Label(root, text="Your password must only be  5 characters long!!", font=notice, bg="#ffefd5", fg="#0000ff", justify=CENTER)
def callback(event):
    if "<0>":
        top = Toplevel(bg="#ffefd5")
        top.title("Koala Encrypter")
        popuptitle = Label(top, text="Your secret number must be between 1 and 9:", font=Body1, fg="red", bg="#ffefd5")
        popuptitle.grid(row = 2,column=0, padx=5, pady = 50,sticky=N+S+E+W)

secret = Label(root, text="SECRET NUMBER: ", font=Body, bg="#ffefd5" , justify=CENTER,)
numbervar = StringVar()

entry2 = Entry(root, textvariable=numbervar , justify=CENTER,relief=SUNKEN,cursor="pencil", takefocus=True) 
entry2.bind("<0>", callback)

Notice2 = Label(root, text="your secret number must be between 1 and 9!!!", font=notice, bg="#ffefd5", fg="#0000ff", justify=CENTER)

img = ImageTk.PhotoImage(Image.open("Koalalogo.jpg"))
panel = Label(root, image = img, relief=SUNKEN)

correct= Label(root, text="Check the below details \n\n Click \'yes\' if they are correct \n\n Click \'No\' to go back \n\n", font=Body1, bg="#ffefd5")
yourwebsite = Label(root, text="The Website is  :", font=Body, bg="#ffefd5")#
website1 = Label(root,  font=Body2, bg="#ffefd5",fg= "#00009C", textvariable = website)#
yourpassword = Label(root, text="Your Password is:", font=Body, bg="#ffefd5")
yournumber1= Label(root, font=Body2, bg="#ffefd5",textvariable = numbervar , fg= "#00009C", )
yourpassword1 = Label(root, font=Body2, bg="#ffefd5",textvariable = passwordvar , fg= "#00009C", )
yournumber= Label(root, text="Your Secret Number is:", font=Body, bg="#ffefd5")

def restart():
    Titlemsg.grid_forget()
    correct.grid_forget()
    yourwebsite.grid_forget()
    website1.grid_forget()
    yourpassword.grid_forget()
    yourpassword1.grid_forget()
    yournumber.grid_forget()
    yournumber1.grid_forget()
    panel.grid_forget()
    toolbar.grid_forget()
    yes.grid_forget()
    no.grid_forget()
    entry.delete(0,END)
    entry1.delete(0,END)
    entry2.delete(0,END)
    Titlemsg.grid( row=7, pady=25, sticky=N+S+E+W)
    startpic.grid( row=10,pady=25, )
    Head.grid( row=14, pady=25, columnspan=2, sticky=N+S+E+W)
    toolbar.grid( row=21, )
    end.grid(column =3, row=1, sticky=N+S+E+W)    
    begin.grid(column =2, row=1, sticky=N+S+E+W) 

def start():
    #entry.destroy()
    #entry1.destroy()
    #entry2.destroy()
    toolbar.grid_forget()
    Titlemsg.grid_forget()
    begin.grid_forget()
    Head.grid_forget()
    startpic.grid_forget()   
    web.grid(row=3, column=0, sticky= W+E)
    entry.grid( row=3, column=1, padx=50)
    passw.grid(row=10, column=0)
    Notice1.grid(row=4, sticky=N+S+E+W, columnspan=2)
    entry1.grid(row=10, column=1)
    Notice.grid(row=11,column=0, columnspan=2,)
    secret.grid(row=13, column=0)
    entry2.grid( row=13, column=1)
    Notice2.grid( row=14,column=0, columnspan=2,)
    panel.grid(row=20,columnspan=2, pady=70)
    confirm.grid(column =1, row=1)
    reset.grid(column =2, row=1)
    end.grid(column =3, row=1)
    toolbar.grid(row=21, column=0, columnspan=2)
    Titlemsg.grid(row=0, column=0, columnspan=2, sticky=E+W)

def Reset():
   entry.delete(0,END)
   entry1.delete(0,END)
   entry2.delete(0,END)

def clear_text():
    #entry.destroy()
    #entry1.destroy()
    #entry2.destroy()
    panel.grid_forget()
    entry.grid_forget()
    entry1.grid_forget()
    entry2.grid_forget()
    web.grid_forget()
    Notice.grid_forget()
    passw.grid_forget()
    secret.grid_forget()
    Notice1.grid_forget()
    Notice2.grid_forget()
    confirm.grid_forget()
    reset.grid_forget()
    toolbar.grid_forget()
    Titlemsg.grid_forget()
    Titlemsg.grid(row=0, column=0, columnspan=2, sticky=E+W)
    correct.grid(row=1, column=0, columnspan=2, sticky=E+W)
    yourwebsite.grid(row=2,column=0,sticky=E+W, pady=5)
    website1.grid(row=2, column=1, padx=65,sticky=E+W, pady=5)
    yourpassword.grid(row=4, column=0,sticky=E+W, pady=5)
    yourpassword1.grid(row=4, column=1, padx=65,sticky=E+W, pady=5)
    yournumber.grid(row=6, column=0,sticky=E+W, pady=5)
    yournumber1.grid(row=6, column=1, padx=65,sticky=E+W, pady=5)
    panel.grid(row=8, column=0, columnspan=2, pady=50)
    toolbar.grid(row=10, column=0, columnspan=2)
    yes.grid(column =1, row=1)
    no.grid(column =2, row=1)

def popup():
    top = Toplevel(bg="#ffefd5")
    top.title("Koala Encrypter")
    popuptitle = Label(top, text="Your password is:", font=Body1, fg="red", bg="#ffefd5")
    popuptitle.grid(row = 2,column=0, padx=5, pady = 50,sticky=N+S+E+W)
    pwd= Label(top, font=Body2, text="password", bg="#ffefd5", fg= "#00009C", ) #textvariable = newpassword ,
    pwd.grid(row= 2, column=1,sticky=E+W,padx=15)
    button = Button(top, text="OK", command=top.destroy, relief=RAISED )
    button.grid(column =0,columnspan=2, row=4, sticky=N+S+E+W)

def helpmsg():
    top = Toplevel(bg="#ffefd5")
    top.title("Koala Encrypter")
    popuptitle = Label(top, text="Koala series 1.0 - Koala Encrypter", font=Title, bg="#00FA9A", relief=RAISED,)
    popuptitle.grid(row = 2,column=0, padx=5, pady = 50,sticky=N+S+E+W)
    pwd= Label(top, font=Body, text="Free software to help you keep your acounts safe", bg="#ffefd5") 
    pwd.grid(row= 1,sticky=E+W,)   
    Titlems = Label(top, text="Koala Encrypter", font=Title, bg="#00FA9A", relief=RAISED,)
    Titlems.grid( row=0, pady=25, sticky=N+S+E+W)
    button = Button(top, text="OK", command=top.destroy, relief=RAISED )
    button.grid(column =0,columnspan=2, row=4, sticky=N+S+E+W)

max_len = 5      

def on_write(*args):
     s = website.get()
     if len(s) > max_len:
          website.set(s[:max_len])

website.trace_variable("w", on_write)

max_len1 = 5      
def on_write(*args):
     s = passwordvar.get()
     if len(s) > max_len1:
          passwordvar.set(s[:max_len1])

passwordvar.trace_variable("w", on_write)

max_len2 = 1      

def on_write(*args):
     s = numbervar.get()
     if len(s) > max_len2:
          numbervar.set(s[:max_len2])
numbervar.trace_variable("w", on_write)

toolbar = Frame(root)
reset = Button(toolbar, text="Reset", width=6, command=Reset, cursor="cross", relief=RAISED, takefocus=True )

end = Button(toolbar, text="Quit" ,command=root.destroy, relief=RAISED, cursor="X_cursor", takefocus=True)
end.grid(column =3, row=1, sticky=N+S+E+W)
begin = Button(toolbar, text="Start Encrypting", command=start, relief=RAISED, cursor="star",takefocus=True )
begin.grid(column =2, row=1, sticky=N+S+E+W)
confirm = Button(toolbar, text="Next", command =clear_text,  cursor="star", relief=RAISED,takefocus=True  )

yes = Button(toolbar, text="Yes", command =popup,  cursor="star",  relief=RAISED,takefocus=True  )

no = Button(toolbar, text="No", command =restart,  cursor="pirate", relief=RAISED, takefocus=True  )
toolbar.grid( row=21, )

menu = Menu(root)
root.config(menu=menu)

filemenu = Menu(menu)
menu.add_cascade(label="File", menu=filemenu)
filemenu.add_command(label="Restart", command=restart)
filemenu.add_separator()
filemenu.add_command(label="Exit", command=root.destroy)

helpmenu = Menu(menu)
menu.add_cascade(label="Help", menu=helpmenu, )
helpmenu.add_command(label="About...", command=helpmsg)

app = root
root.mainloop()

# add functionality,  fix validation
Improve this question
7
  • use .get() to get normal Python string from StringVar, do what you want with this string - you can even convert to list of chars - and at the end put new string into StringVar using .set() (if you have list of chars then use join() to conver into string). BTW: you don't have to use StringVar if you don't want it. You can get text directly from Entry - entry.get() Commented Jan 14, 2017 at 6:11
  • Entry has option validatecommand= and you can assing function which will check text - effbot.org/tkinterbook/entry.htm Commented Jan 14, 2017 at 6:16
  • BTW: we use CamelCase names only for classes - to make code more readable (see: Button, Label, etc). For variables and functions we use lower_case names. Commented Jan 14, 2017 at 6:18
  • I've tried get() but it still gives an error, getitem or something similar. As for the validate command, I'm not sure how to use it, I have researched it though but in the end I'll still need the stringvar as a string that lets me access its indexes (indices) but I'm not sure how to do that. I've exhausted every resource on the internet trying to do so. I think its probably just because i don't have the knowledge to comprehend the information given on the links i've been reading.How can I use text directly,if I use text it won't let me output the data into the labels?What is CamelCase? Commented Jan 14, 2017 at 6:37
  • when I write .get() with dot at the beginning I mean text = password.get(), text = websit.get(), etc. The same password.set(text), website.set(text), etc. Commented Jan 14, 2017 at 6:42

1 Answer 1

Reset to default
2

To restrict the type/number of characters that can be typed into an entry widget, you can use the entry validatecommand. Here is an example to allow only letters and another one to restrict the entry to 4 digits:

from tkinter import Tk, Entry, Label

def only_letters(action, char):
    if action == "1":
        # a character is inserted (deletion is 0) allow the insertion 
        # only if the inserted character char is a letter
        return char.isalpha()
    else:
        # allow deletion
        return True

def only_numbers_max_4(action, new_text):
    if action == "1":
        return new_text.isdigit() and len(new_text) <= 4
    else:
        return True

root = Tk()
# register validate commands
validate_letter = root.register(only_letters)
validate_nb = root.register(only_numbers_max_4)

Label(root, text="Only letters: ").grid(row=0, column=0)
e1 = Entry(root, validate="key", validatecommand=(validate_letter, '%d', '%S'))
# %d is the action code and %S the inserted/deleted character
e1.grid(row=0, column=1)

Label(root, text="Only numbers, at most 4: ").grid(row=1, column=0)
e2 = Entry(root, validate="key", validatecommand=(validate_nb, '%d', '%P'))
# %P is the new content of the entry after the modification
e2.grid(row=1, column=1)

root.mainloop()

For more details on entry validation, see http://infohost.nmt.edu/tcc/help/pubs/tkinter/web/entry-validation.html

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