How to Get Value from Spinbox in Tkinter

Posted on By Pythoneo

One of the widgets that Tkinter provides is the Spinbox

The Spinbox widget allows you to select a value from a fixed range of numbers or a list of values. We will learn how to create a Spinbox widget and how to get the value that the user has selected.

Creating a Spinbox widget

To create a Spinbox widget, you need to import the Tkinter module and create a root window:

import tkinter as tk

root = tk.Tk()

Then, you can use the tk.Spinbox constructor to create a Spinbox widget and add it to the root window. The constructor takes several options, but the most important ones are:

  • from_ and to: These specify the minimum and maximum values of the range that the user can select. Note that from_ has an underscore at the end to avoid conflict with the Python keyword from.
  • values: This specifies a tuple of discrete values that the user can select. If this option is given, the from_ and to options are ignored.
  • textvariable: This specifies a tk.StringVar object that holds the current value of the Spinbox. You can use this option to link the Spinbox value to other widgets or variables.
  • command: This specifies a function that will be executed whenever the value of the Spinbox changes.
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For example, the following code creates a Spinbox widget that allows the user to select a number from 1 to 10:

spin_value = tk.StringVar(value=1) # create a StringVar object to store the Spinbox value
spin_box = tk.Spinbox(root, from_=1, to=10, textvariable=spin_value) # create a Spinbox widget
spin_box.pack() # add the Spinbox widget to the root window

Alternatively, you can create a Spinbox widget that allows the user to select a color from a list of values:

colors = ("Red", "Green", "Blue", "Yellow", "Pink") # create a tuple of colors
spin_value = tk.StringVar(value=colors[0]) # create a StringVar object to store the Spinbox value
spin_box = tk.Spinbox(root, values=colors, textvariable=spin_value) # create a Spinbox widget
spin_box.pack() # add the Spinbox widget to the root window

Getting the value from a Spinbox widget

There are two ways to get the value that the user has selected from a Spinbox widget:

  • You can use the get() method of the tk.StringVar object that is linked to the textvariable option of the Spinbox. For example:
print(spin_value.get()) # print the current value of the spin_value StringVar object
  • You can use the get() method of the Spinbox widget itself. For example:
print(spin_box.get()) # print the current value of the spin_box Spinbox widget

Both methods will return a string representation of the selected value. If you want to convert it to another data type, such as an integer or a float, you can use the built-in functions int() or float(). For example:

num = int(spin_box.get()) # convert the current value of the spin_box Spinbox widget to an integer
print(num + 1) # print one more than the selected number

Executing a function when the value changes

If you want to perform some action when the user changes the value of the Spinbox widget, you can use the command option to specify a function that will be executed automatically. For example, suppose you want to change the background color of the root window according to the color selected by the user in the Spinbox widget. You can define a function like this:

def change_color():
    color = spin_value.get() # get the current value of the spin_value StringVar object
    root.config(bg=color) # change the background color of the root window

Then, you can pass this function as an argument to the command option when creating the Spinbox widget:

spin_box = tk.Spinbox(root, values=colors, textvariable=spin_value, command=change_color) # create a Spinbox widget with command option

Now, whenever you select a different color in the Spinbox widget, you will see that the background color of the root window changes accordingly.

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Tkinter