# Arguments

> Markdown source of <https://docs.calebsargeant.com/programming/python/other/args/>.

## Argparse

<https://stackabuse.com/command-line-arguments-in-python/>

<http://zetcode.com/python/argparse/>

<https://stackoverflow.com/questions/22570407/how-to-store-argparse-values-in-variables>

Gentleman's agreement: optional arguments should be flags, and required arguments should be positional.

``` python
# Positional arguments
import argparse

parser = argparse.ArgumentParser(description="Do this and that")
parser.add_argument("arg1", help="arg1 is for this")
parser.add_argument("arg2", help="arg2 is for that")
parser.add_argument("arg3", help="arg3 is for the other")
args = parser.parse_args()

print(args.arg1)
print(args.arg2)
print(args.arg3)

# Flagged arguments
import argparse

parser = argparse.ArgumentParser(description="Do this and that")
parser.add_argument("--arg1", "-a", help="arg1 is for this", required=True)
parser.add_argument("--arg2", "-b", help="arg2 is for that", required=True)
parser.add_argument("--arg3", "-c", help="arg3 is for the other", required=True)
args = parser.parse_args()

print(args.arg1)
print(args.arg2)
print(args.arg3)
```