How do I get the index of an item in Tkinter.Listbox?

We use the Tkinter Listbox widget to create a list of items. Each item in the listbox has sequential indexes assigned to them in vertical order starting from 0.

To get the index of a clicked item in the listbox, we use the curselection() method which returns a tuple of selected item indexes. We can then access specific items using the get() method.

Basic Example

Here's how to get the index of selected items in a Listbox ?

# Import the required libraries
from tkinter import *

# Create an instance of tkinter frame or window
win = Tk()

# Set the size of the window
win.geometry("700x350")

# Create a Listbox widget
lb = Listbox(win, width=50, height=10, font=('Times', 13), selectbackground="lightblue")
lb.pack(pady=20)

# Define a function to get selected item index
def get_selection():
    for item in lb.curselection():
        print(f"Index: {item}, Value: {lb.get(item)}")

# Add items in the Listbox
items = ["Apple", "Banana", "Cherry", "Date", "Elderberry", "Fig"]
for item in items:
    lb.insert("end", item)

# Add a Button to get selection
Button(win, text="Get Selected Index", command=get_selection, font=('Times', 12)).pack(pady=10)

win.mainloop()

Key Methods

Multiple Selection Example

For listboxes that allow multiple selections, you can handle all selected indexes ?

from tkinter import *

win = Tk()
win.geometry("600x400")

# Create Listbox with multiple selection mode
lb = Listbox(win, selectmode=MULTIPLE, width=40, height=8)
lb.pack(pady=20)

def show_all_selections():
    selected_indexes = lb.curselection()
    if selected_indexes:
        print("Selected items:")
        for index in selected_indexes:
            print(f"Index {index}: {lb.get(index)}")
    else:
        print("No items selected")

# Add sample items
colors = ["Red", "Green", "Blue", "Yellow", "Purple", "Orange", "Pink"]
for color in colors:
    lb.insert("end", color)

Button(win, text="Show All Selections", command=show_all_selections).pack(pady=10)

win.mainloop()

Event-Driven Selection

You can also bind events to automatically detect when an item is selected ?

from tkinter import *

win = Tk()
win.geometry("500x300")

lb = Listbox(win, width=30, height=6)
lb.pack(pady=20)

def on_select(event):
    selection = lb.curselection()
    if selection:
        index = selection[0]
        value = lb.get(index)
        print(f"Selected index: {index}, value: {value}")

# Bind selection event
lb.bind('<<ListboxSelect>>', on_select)

# Add items
fruits = ["Mango", "Orange", "Grapes", "Strawberry"]
for fruit in fruits:
    lb.insert("end", fruit)

win.mainloop()

Conclusion

Use curselection() to get selected item indexes and get(index) to retrieve values. Bind the <<ListboxSelect>> event for automatic selection detection in interactive applications.