I am trying to work my way through Tkinter and this is a part of my code:
FirstName = Label(canvas, text="First Name")
FirstName.configure(width=30, bg="white", fg="black", border=10)
FirstName = canvas.create_window(330, 130, anchor = CENTER, window=FirstName)
FName_Entry = Entry(canvas)
canvas.create_window(850, 145, window=FName_Entry, height=35, width=300)
As you can see this is an entry widget for users to enter their first name.
how can I validate this to only accept string (letters) and if they try to enter integers, symbols or basically anything that is not a letter, it should display a message on the side of the widget urging users to enter a valid name.
I tried to check online but most of them are using classes and I am not used to classes as of yet and am new to Tkinter. other examples explain how to limit entry to integers so I am a bit confused here.
Thanks for helping!
Here is a small snippet to actually make you understand better
from tkinter import *
from tkinter import messagebox
root = Tk()
def check():
sel = e.get()
if not sel.isalpha():
messagebox.showerror('Only letters','Only letters are allowed!')
e = Entry(root)
e.pack(pady=10)
b = Button(root,text='Click Me',command=check)
b.pack(padx=10,pady=10)
root.mainloop()
Here we are checking if sel.isalpha() returns False or not, if it does, then show a messagebox saying only letters are allowed. Simple as that.
Do let me know if any errors. Happy coding
Here is more on isalpha() method
Cheers
You can use list in which you can store the letter which is to be accepted.
Then check the each letter of the input with the element in the list.
If any character not found from the input in the list(acceptable character) then it is invalid input.
# acceptable character list
accepted_characters = ['a', 'b', 'c',.....'z', 'A', 'B', 'C',...'Z']
# input from the tkinter entry widget
inp = "hello"
for i in inp:
if i not in accepted_characters:
print('Invalid data.')
Another way is using RegEx module which is built-in module. But I am not too familiar with RegEx.
Related
I am Python coder and got stuck in a question that "How to check input in textbox of tkinter python". The problem is that it is not giving output on writing this code .
def start(event):
a = main.get(1.0,END)
if a == 'ver':
print('.....')
main = Text(root)
main.pack()
root.bind('<Return>',start)
We can do this by get() method:
from tkinter import *
a=Tk()
def check():
print(x.get('1.0',END)[:-1])
x=Text(a)
b=Button(a,text='Check',command=check)
x.pack()
b.pack()
a.mainloop()
The text widget guarantees that there is always a trailing newline. When you do get(1.0,END) you're getting that trailing newline even if the user doesn't enter a newline.
If you want to get exactly what the user entered, use get("1.0", "end-1c"). That will get all of the characters up to the end, minus one character.
Note: text indexes are strings of the form line.character. Your code is using the floating point value 1.0 which is incorrect. It works fine in some cases, but it won't work in all. You should always use a string rather than a float for text indexes.
from tkinter import *
from threading import Thread
root = Tk()
def check():
while True :
a = main.get(1.0,END)[:-1]
if a == 'ver':
print('.....')
main = Text(root)
main.pack()
Thread(target=check).start()
root.mainloop()
You should write something like
def start(event):
t = var.get()
if t == 'something':
pass
var = StringVar()
e = Entry(master, textvariable=var)
e.pack()
e.bind(bind('<Return>',start)
from tkinter import *
window = Tk()
window.title("Registration")
window.configure(background="blue")enter code here
Label (window, text= "Firstname: ", bg="blue", fg="white", font="verdana 12 bold") .grid(row=0, sticky=E)
firstname = Entry(window, width=100, bg="white")
firstname.grid(row=0, column=1, sticky=W)
firstname = firstname.get()
firstname = firstname.strip()
firstname = firstname.lower()
Label (window, bg = "blue") .grid(row=2)
Label (window, text= "Surname: ", bg="blue", fg="white", font="verdana 12 bold") .grid(row=3, sticky=E)
surname = Entry(window, width=100, bg="white")
surname.grid(row=3, column=1, sticky=W)
surname = surname.get()
surname = surname.lower()
surname = surname.strip()
Label (window, bg = "blue") .grid(row=4)
Label (window, text = "Pick a number between 0 and 10: ", bg="blue", fg="white", font = "verdana 12 bold") .grid(row=5, sticky=E)
number = Entry(window, width=100, bg="white")
number.grid(row=5, column=1)
while True:
try:
number = number.get()
if (number > 10) or (number < 0): 1/0
except:
print("Sorry, your response must be a number between 0 and 10")
continue
break
window.mainloop()
This is my code so far. I am trying to create a registration system for a quiz I'm making, however, now that I am dealing with GUI, I don't know how to use my validation code in the GUI way/environment. for example, just having "print("sorry, your response must be a number between 0 and 10")" won't and isn't working with my program.
My question: How do I output a message into a textbox like an error message and how do I implement my validation code?
Also, I made my validation code onths ago when I was new to python and used a stack overflow piece of code to help apply it to my program. Anyway, could someone help explain how this code actually works. I don't seem to understand it now and my teacher has struggled to explain it in an understandable way. Specifically the : 1/0 bit. I'm not used to using try and except, I only know how to use for and while loops usually.
Many thanks
Showing messages in tkinter (1st question)
To show the user basic massages and get basic options (show an error, ask OK/Cancel or yes/no...) you can use tkinter.messagebox. It provides show*() and ask*() functions. In your case, showerror() or showwarning() is probably best.
To get basic input, tkinter.simpledialog can be used. It provides the functions askinteger, askfloat and askstring that will ask the user for the respective data type.
To get file (path) input, use tkinter.filadialog.
For more complex situations, it is best you use the tkinter.Toplevel widget.
2nd question
Your code
I am going to play interpreter and go through your code. If you just want the solutions (not recommended), jump below.
firstname = Entry(...) => create an Entry widget and assign it to firstname
firstname.grid(...) => put the widget in/on the window
firstname = firstname.get() => get the text currently in the widget and assign it to firstname.
OK, you want to get the text. Just, the window isn't even visible yet. These instructions will work in the IDLE shell, because of special reasons and you wait to call .get() until you typed your name. In "real" execution, the interpreter won't wait and your user can't type (because there isn't a window) before you call .mainloop(). One solution, if you read above, is to use simpledialog. But also this should run after the GUI started, i.e. after .mainloop() is called. I'll get to that part later.
-- same for surname --
Your validation
Interpreter:
number = Entry(...) => create a new Entry widget and assign it to number
number.grid(...) => show it
# while True here
# try here
number = number.get() => call number.get() and assign the value (a str) to number -- keep that in mind
# if condidtion below
number > 10 => check if a str is larger/greater than an int; can't do that, raise a TypeError
# error -> go to the except
print("I asked how to do this on SO") => show this (in the console); in future hopefully via messagebox
continue => go to the beginning of the loop
# in try
number = number.get() => call the .get() method of the str number; can't find it, raise an AttributeError
# error -> go to the except
print(...) => as before
continue => as before
You get caught in an infinite loop of exception that won't stop even if the user enters a correct number (which can't happen anyway, we don't have a window yet). This is a very good reason for avoiding a bare except - you will also catch lots of stuff you don't want.
Why the method you are trying to use wooooould work (you said you found it here -- do you still have a link or remember the title?):
Code (this example in the console for simplicity):
while True:
try:
value = int(input())
if not 0<value<10:
1/0
except ZeroDivisionError: # let ValueError through (you willl want to catch it separately)
print('by executing 1/0, I raised a ZeroDivisionError. This code therefore will execute.')
else:
print('Everything did fine. I will exit the loop to continue.')
break
Interpreter:
# loop
# in try
value = int(input()) => read input and try to convert to an int; we assume this doesn't fail.
# if condition
not 0<value<10 => is value not between 0 and 10? (we assume it isn't)
# if block
1/0 => what?!? I can't do that, I'll raise a ZeroDivisionError
# except block
print(...) => show the text
# loop again
# in try
value = int(input()) => as above
# if condition
not 0<value<10 => we assume value is between 0 and 10 (evaluetes to False)
# else part of the try...except...else
print(...) => show text
break => exit the loop
You intentionally perform 1/0, which will raise a ZeroDivisionError and act on that in the except. Since you said you don't usually do it, I recommend you try to understand what it does.
How to do it better
Make the window appear before expecting user input: Put all code that should execute at application start in a function and either delay it with tkinter.Tk.after (window.after) or add a nice "Start!"
Button.
Don't (ab)use exceptions when a simple if will do (if you really want to (show off), define your own class MyFancyException(Exception): pass)
Look up on concepts you don't understand before using them and insert comments to remind you if something is so complicated you're afraid you won't remember later.
.
import tkinter as tk
from tkinter.simpledialog import askstring, askinteger
from tkinter.messagebox import showwarning
def do_stuff(first_name, surname, number):
...
def start():
# if you want to use Entry, add a "Submit" Button
first_name = askstring('Title', 'first name:')
surname = askstring('Title', 'last name:')
while True: # ask* return None when cancel is pressed
number = askinteger('Title', 'insert a number between 0 and 10:')
if number is not None and 0<number<10: # what we want
break
do_stuff(first_name, surname, number)
# GUI preparation code
window = tk.Tk()
button_start = tk.Button(window, text='Start!', command=start)
button_start.pack() # for use with other widgets (that use grid), you must .grid() here
window.mainloop() # the GUI appears at this moment
I've been having a lot of difficulties with this code, and I just can't find any solutions, I will post my code below.
from tkinter import *
a = []
class test(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
self.parent = parent
self.parent.title('testing')
self.pack(fill=BOTH, expand=1)
self.d = DoubleVar()
self.d.set('None')
def grab():
b = ent.get()
a.append(b)
c = [s.strip('qwertyuiopasdfghjklzxcvbnm') for s in a]
self.d.set(c[-1])
if c[-1] == '':
self.d.set('None')
ent = Entry(self)
ent.grid(row=0, column=0)
but = Button(self, text='Get', command=grab)
but.grid(row=1, column=0)
Label(self, textvariable=self.d).grid(row=2, column=0)
root = Tk()
app = test(root)
root.mainloop
I guess my objective is to be able to ignore, or delete the letters that are placed inside of the entry box, as you can see, I've used the strip method, but it doesn't work the way I would like it to. If anyone could offer some advice, or a code, or link me to a question that I overlooked, that would be amazing, and I would be greatful.
EDIT: It already clears letters before and after, but nothing in between
A validator would be the correct pattern to solve this problem. Interactively validating Entry widget content in tkinter has an implementation in tkinter that you should be able to use.
A little bit of lambda should do the trick
a = "123a3456b"
filter(lambda '0' <= x <= '9', a)
print a
"1233456"
You're getting letters inside the numbers because you're putting the string into a list first.
strip() removes leading and trailing characters, so if you have a string: aaa000bbb111ccc, stripping letters from it will only remove the outer-most letters. If you split the string, however, and then strip letters from each element of the stripped string, you'll effectively remove all the letters. Then, you can join() the remaining parts of the list together to get back to your string. Consider this example:
>>> import string # string.ascii_letters returns a string of all letters (upper and lower), just easier than typing them
>>> def check(x):
return ''.join([char.strip(string.ascii_letters) for char in x])
>>> var = 'aaa000bbb111ccc'
>>> var_as_list = [var]
>>> check(var)
'000111'
>>> check(var_as_list)
'000bbb111'
So, c should be:
c = ''.join([s.strip('qwertyuiopasdfghjklzxcvbnm') for s in b.get()])
You should also consider some further validation, if you want the field to only contain floats. Here's one method to trace any changes to a StringVar() instance and restrict changes to it to only being numbers and periods:
from tkinter import *
import string
def check(*args):
# make a 'whitelist' of allowable characters
whitelist = string.digits + '.'
# set var to its current value - any characters not in whitelist
var.set(''.join([i for i in var.get() if i in whitelist]))
root = Tk()
var = StringVar()
var.set('0.0')
Entry(root, textvariable=var).grid(row=0, column=0)
Label(root, textvariable=var).grid(row=1, column=0)
var.trace('w', check) # if var changes, call check()
mainloop()
a clean way to do this is simply:
filter(lambda s: not str.isalpha(s), data)
I'm working on a "Password Generator" that will generate a string of random characters. I would like to add a 'Copy' button that when clicked will take that random string and add it to the clipboard so that it can be pasted elsewhere.
I thought I had it worked out with my current code as I stopped getting error messages but whenever I try to paste the password I get something like "<function genpass at 0x029BA5F0>".
import random
from swampy.Gui import *
from Tkinter import *
import string
#--------Globals-------
pcha = string.ascii_letters + string.punctuation + string.digits
g = Gui()
#--------Defs---------
def genpass():
return "".join(random.choice(pcha) for i in range (10))
def close():
g.destroy()
def copy():
g.withdraw()
g.clipboard_clear()
g.clipboard_append(genpass)
#--------GUI----------
g.title("Password Helper")
g.la(text="Welcome to Password Helper! \n \n Choose from the options below to continue. \n")
rndpass = StringVar()
update = lambda:rndpass.set(genpass())
btna = g.bu(text="Generate a New Password", command=update)
btna.pack(padx=5)
pbox = g.en(textvariable = rndpass)
pbox.config(justify='center')
pbox.pack( padx = 5)
btnb=g.bu(text ="Copy to Clipboard", command=copy)
btnc=g.bu(text ="Exit", command=close)
g.mainloop()
I feel like I'm missing just one little thing that would solve my problem but I just can't guess what it is. I've been searching around and found a few possible solutions (even pyperclip) but no matter how I try them I always end up with the same outcome. Any help is greatly appreciated.
This line:
g.clipboard_append(genpass)
is adding the function genpass, rather than its return value
You need to call the function with ():
g.clipboard_append(genpass())
Edit: It looks like you're storing the password in rndpass. So to get that back out, you need to call rndpass.get():
g.clipboard_append(rndpass.get())
My program should check if the first three letters of the input word are similar to a predefined word.
I've made a GUI with Tkinter and want to get the letters of the input field.
Somehow I can't implement it in like I would do without Tkinter.
That's how I do it just for the shell:
text = raw_input('Enter a word: ')
if (text[0] + text[1] + text[2] == 'sag'):
print "sagen"
else:
print "error"
So, when I input the word "sagst" it checks the first three letters and should put out "sagen". Works fine.
I learned that e.g. inputfield.get() gets the input of the entry "inputfield".
But how can I check the first letters of that "inputfield"?
A small selection:
from Tkinter import*
root = Tk()
def check():
if (text[0] + text[1] + text[2] == 'sag'):
print "True"
else:
print "False"
inputfield = Entry(root)
inputfield.pack()
but = Button(root,text='Check!', command = check)
but.pack()
text = inputfield.get()
root.mainloop()
Does not work...
I hope you can understand my question and will answer soon. (Sorry for my bad english and my bad Python skills) ;-)
Thanks!
Your check function will have to retrieve the textfield after the button has been pressed:
def check():
text = inputfield.get()
print text.startswith('sag')
I've changed your test a little, using .startswith(), and directly printing the result of that test (print will turn boolean True or False into the matching string).
What happens in your code is that you define inputfield, retrieve it's contents (obviously empty), and only then show the TKInter GUI window by running the mainloop. The user never gets a chance to enter any text that way.
You can also check this without the need for a button (Now it will check whenever the user presses "Enter"):
from Tkinter import *
root = Tk()
def check(*event):
text = inputfield.get()
print text.startswith('sag')
inputfield = Entry(root)
inputfield.bind('<Return>',check)
inputfield.pack()
root.mainloop()
You can also do other things to have your widget validate the entry as you type. (The link is old, but it also points to newer features that allow you to do this without subclassing).
You're not actually putting the value in the input field into the text variable.
I renamed the value from text to input_text because it was confusing to me. I also changed from using text[0] + text[1] + text[2] to using startswith(). This will keep you from getting IndexErrors on short strings, and is much more pythonic.
from Tkinter import*
root = Tk()
def check():
input_text = inputfield.get()
if input_text.startswith('sag'):
print "True"
else:
print "False"
inputfield = Entry(root)
inputfield.pack()
input_text = inputfield.get()
print input_text # Note that this never prints a string, because it only prints once when the input is empty.
but = Button(root, text='Check!', command=check)
but.pack()
root.mainloop()
The key change is that the check function needs to actually get the value in the inputfield.
Here is a version which uses an Entry widget which validates its contents as the user types (so the user does not have to click a button or even press Return).
import Tkinter as tk
class MyApp(object):
'''
http://effbot.org/zone/tkinter-entry-validate.htm
http://effbot.org/tkinterbook/entry.htm
http://www.tcl.tk/man/tcl8.5/TkCmd/entry.htm#M-validate
'''
def __init__(self, master):
vcmd = (master.register(self.validate),
'%d', '%i', '%P', '%s', '%S', '%v', '%V', '%W')
self.entry = tk.Entry(master, validate = 'key',
validatecommand = vcmd)
self.entry.pack()
self.entry.focus()
def validate(self, action, index, value_if_allowed,
prior_value, text, validation_type, trigger_type, widget_name):
dtype = {'0':'delete', '1':'insert', '-1':'other'}[action]
n = min(3, len(value_if_allowed))
valid = False
if dtype == 'insert':
if value_if_allowed[:n] == 'sag'[:n]: valid = True
else: valid = False
else: valid = True
print(valid)
return True
root = tk.Tk()
app = MyApp(root)
root.mainloop()