Python Arguments

 In Python, arguments are values that are passed to functions, methods, or classes when they are called. Arguments can be used to provide additional information to the function, method, or class, or to change the way that it behaves.

There are two types of arguments in Python: positional arguments and keyword arguments.

  • Positional arguments are arguments that are passed to a function, method, or class in the order that they are defined. For example, the following function takes two positional arguments:
Python
def my_function(arg1, arg2):
  print(arg1, arg2)

To call this function, you would pass two arguments, in the order that they are defined:

Python
my_function(1, 2)
  • Keyword arguments are arguments that are passed to a function, method, or class using the keyword keyword. Keyword arguments can be passed in any order, and they do not need to be defined in the same order as they are defined in the function, method, or class. For example, the following function takes two keyword arguments:
Python
def my_function(arg1, arg2):
  print(arg1, arg2)

To call this function, you could pass the arguments in any order, and you could also use the keyword keyword to specify the name of the argument:

Python
my_function(arg1=1, arg2=2)
my_function(arg2=2, arg1=1)

You can also mix positional arguments and keyword arguments:

Python
my_function(1, arg2=2)

In this case, the first argument is a positional argument, and the second argument is a keyword argument.

Arguments are a powerful way to customize the behavior of functions, methods, and classes. By using arguments, you can make your code more flexible and reusable.

Here are some additional things to keep in mind about arguments in Python:

  • Default values: You can specify default values for arguments. This means that if the argument is not passed to the function, method, or class, it will be set to the default value. For example, the following function takes one argument, arg1. The default value for arg1 is 10:
Python
def my_function(arg1=10):
  print(arg1)

To call this function without passing any arguments, the value of arg1 will be 10:

Python
my_function()
  • Required arguments: You can specify that an argument is required. This means that the function, method, or class will not work properly if the argument is not passed. For example, the following function takes one required argument, arg1:
Python
def my_function(arg1):
  print(arg1)

To call this function, you must pass the argument arg1:

Python
my_function(10)

If you try to call this function without passing the argument arg1, you will get an error:

Python
my_function()
  • Argument validation: You can validate arguments to make sure that they are of the correct type or within a certain range. For example, the following function takes one argument, arg1. The argument arg1 must be a string:
Python
def my_function(arg1):
  if not isinstance(arg1, str):
    raise ValueError("arg1 must be a string")

  print(arg1)

To call this function, you must pass a string as the argument arg1:

Python
my_function("Hello, world!")

If you try to call this function with a non-string argument, you will get an error:

Python
my_function(10)

Argument validation is a powerful way to ensure that your code is robust and that it can handle unexpected input.

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