Intuitive Python

Getting Caught with Sticky Default Arguments

Python allows you to specify arguments with defaults in your function signatures. For example, consider the use_exclamation argument in the print_greeting function:

def print_greeting(name, use_exclamation=False):
    greeting = "Hello " + name
    if use_exclamation:
        greeting += "!"
    print(greeting)

In the above example, the use_exclamation argument to the print_greeting function has a default value of False. Since use_exclamation defaults to False, print_greeting("David") outputs Hello David (with no trailing ! character). If we provided a value for the use_exclamation argument, however, the output changes. print_greeting("David", use_exclamation=True) outputs Hello David! because the ...