Argparse is a powerful library in Python for parsing command-line arguments. It provides a convenient way to define various options and arguments that can be passed to a Python script when executed from the command line. One of the key features of argparse is the ability to set default values for these arguments.

In some cases, you may want to override the default values of argparse arguments programmatically, rather than manually specifying them on the command line every time. This can be useful when you have a predefined set of default values but need to change them dynamically based on certain conditions or inputs.

To override argparse default values programmatically, you can follow these steps:

1. Import the argparse module.

   import argparse
   

2. Create an instance of the ArgumentParser class.

   parser = argparse.ArgumentParser()
   

3. Define the desired command-line arguments using the add_argument method, including the default values.

   parser.add_argument('--option', default='default_value', help='Description of the option')
   

4. Parse the command-line arguments.

   args = parser.parse_args()
   

5. Override the default value of an argument if needed.

   if some_condition:
    args.option = 'new_value'
   

Now, when you access the value of the --option argument later in your code, it will reflect the updated value if the condition is met.

Here’s a complete example demonstrating the code flow:

import argparse

parser = argparse.ArgumentParser()
parser.add_argument('--option', default='default_value', help='Description of the option')
args = parser.parse_args()

if some_condition:
    args.option = 'new_value'

# Access the value of the argument
print(args.option)

In this example, if the some_condition evaluates to True, the value of args.option will be 'new_value'. Otherwise, it will be 'default_value'.

By overriding argparse default values programmatically, you can have more control over the behavior of your script and modify the argument values based on specific conditions or inputs.