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Functions & basics

Reusable building blocks — parameters, returns, scope, and clear function design.

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Functions & basics easy

How to Add a Dry Run Flag to a Python CLI Command

Build a Python CLI command with a --dry-run flag that previews actions and exits before making real changes.

argparse cli dry-run
Python
import argparse
import sys

def main():
    parser = argparse.ArgumentParser(description="Sample CLI command with dry-run flag")
    parser.add_argument("--name", required=True, help="Name to greet")
    parser.add_argument("--dry-run", action="store_true", dest="dry_run",
                        help="Show what would…
11 0 Open
Functions & basics easy

How to Parse Command Line Arguments in Python with argparse

Build a CLI that accepts positional integers, an optional --sum flag, and a --verbose switch, all with Python's standard argparse library.

argparse cli command line
Python
import argparse

def main():
    parser = argparse.ArgumentParser(description='Process some integers.')
    parser.add_argument('numbers', metavar='N', type=int, nargs='+',
                        help='an integer for the accumulator')
    parser.add_argument('--sum', dest='accumulate', action='store_const',
         …
11 0 Open
Functions & basics easy

How to Validate CLI Integer Option Within a Range in Python

Use argparse with integer type and bounds checking to validate a command-line option falls within a specified min-max range.

argparse cli validation
Python
import argparse

def main():
    parser = argparse.ArgumentParser(description="Validate an integer within a range.")
    parser.add_argument("--value", type=int, required=True, help="Integer to validate")
    parser.add_argument("--min", type=int, default=0, help="Minimum allowed value")
    parser.add_argument("--max…
13 0 Open

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Functions & basics — Python code examples

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This page collects functions & basics snippets — short, copy-ready Python you can paste into our free online IDE and run without installing anything. Each sample includes a plain-English explanation and the full source code.

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