Autocomplete ComboBox in Python-Tkinter

Last Updated : 12 Jul, 2025

Prerequisites: Python GUI – tkinter The Listbox widget is used to display a list of items from which a user can select a number of items. But have you ever wondered, how to return the list of possible results when a key is pressed? Let's see the following approach towards the same. Working of Program

List consisting of words is initialized.
Entry box and Listbox are created and are added to the root window.
Bind function is used for event handling. Key release event is handled for an Entry field.
When any key is pressed in the Entry, checkkey() function is called.
checkkey() function then compares the entered string with existing list keywords and populates Listbox with matching keywords.
Then this data is sent to update function which then updates the Listbox.

Below is the approach.

Python 1==

from tkinter import *
 
    
# Function for checking the
# key pressed and updating
# the listbox
def checkkey(event):
     
    value = event.widget.get()
    print(value)
    
    # get data from l
    if value == '':
        data = l
    else:
        data = []
        for item in l:
            if value.lower() in item.lower():
                data.append(item)                
 
    # update data in listbox
    update(data)
 
 
def update(data):
    
    # clear previous data
    lb.delete(0, 'end')
 
    # put new data
    for item in data:
        lb.insert('end', item)


# Driver code
l = ('C','C++','Java',
     'Python','Perl',
     'PHP','ASP','JS' )

root = Tk()

#creating text box 
e = Entry(root)
e.pack()
e.bind('<KeyRelease>', checkkey)

#creating list box
lb = Listbox(root)
lb.pack()
update(l)
 
root.mainloop()