How to get a number as Input in Tkinter?

• tinyytopic.com
• 0
• on Mar 21, 2023

This Python function gets input from the user using the Tkinter input window. Ready-to-use Python function to get an Integer or Float number:

def get_number_input(header, prompt, root, number_type):
    
    # Get an Integer number
    if number_type == 'integer' or number_type == 'Integer' or number_type == 'int' or number_type == 'Int':
        while True:
            try:
                number_str = simpledialog.askinteger(header, prompt, parent=root)
                break
            except ValueError:
                print("That's not an integer. Please try again.")
                number_str = None
        return number_str
    
    # Get a float number
    elif number_type == 'float' or number_type == 'Float':
        while True:
            try:
                number_str = simpledialog.askfloat(header, prompt, parent=root)
                break
            except ValueError:
                print("That's not a float. Please try again.")
                number_str = None
        return number_str

Write your main code as a sample below,

header = 'Number Entry'
prompt = 'Enter an Integer number: '
number_type = 'Integer'
number = get_number_input(header, prompt, root, number_type)
print(number)

or

header = 'Number Entry'
prompt = 'Enter a decimal number: '
number_type = 'Float'
number = get_number_input(header, prompt, root, number_type)
print(number)

A Sample Integer Output:
150

A Sample Decimal Output:
12.35

This is a Python function called get_number_input that accepts four parameters: header, prompt, root, and number_type. Here’s how it works:

1. The function starts by checking whether the number_type parameter is set to 'integer', 'Integer', 'int', or 'Int'. If it is, the function uses a while loop to repeatedly ask the user for an integer input using the simpledialog.askinteger function. If the user enters a value that cannot be converted to an integer, a ValueError exception is raised, and the loop continues. Once the user enters a valid integer, the function returns that integer value.
2. If the number_type parameter is set to 'float' or 'Float', the function uses a similar while loop to ask the user for a float input using the simpledialog.askfloat function. Again, if the user enters a value that cannot be converted to a float, a ValueError exception is raised, and the loop continues. Once the user enters a valid float, the function returns that float value.
3. If the number_type parameter is not set to 'integer', 'Integer', 'int', 'Int', 'float', or 'Float', the function does not do anything and simply returns None.

Overall, this function can be used to get either an integer or a float input from the user, depending on the value of the number_type parameter. If the user enters an invalid value, the function will continue to prompt them until they enter a valid one.