Sample code for the Click article

python-click/README.md

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+# Click and Python: Build Extensible and Composable CLI Apps
+
+This folder provides the code examples for the Real Python tutorial [Click and Python: Build Extensible and Composable CLI Apps](https://realpython.com/python-click/).

python-click/add.py

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+import click
+
+
+@click.command()
+def cli():
+    a = click.prompt("Enter an integer", type=click.INT, default=0)
+    b = click.prompt("Enter another integer", type=click.INT, default=0)
+
+    click.echo(f"{a} + {b} = {a + b}")
+
+
+if __name__ == "__main__":
+    cli()

python-click/calc_v1.py

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+import click
+
+
+@click.group()
+def cli():
+    pass
+
+
+@cli.command()
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def add(a, b):
+    click.echo(a + b)
+
+
+@cli.command()
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def sub(a, b):
+    click.echo(a - b)
+
+
+@cli.command()
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def mul(a, b):
+    click.echo(a * b)
+
+
+@cli.command()
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def div(a, b):
+    click.echo(a / b)
+
+
+if __name__ == "__main__":
+    cli()

python-click/calc_v2/calc.py

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+import click
+import commands
+
+
+@click.group()
+def cli():
+    pass
+
+
+cli.add_command(commands.add)
+cli.add_command(commands.sub)
+cli.add_command(commands.mul)
+cli.add_command(commands.div)
+
+if __name__ == "__main__":
+    cli()

python-click/calc_v2/commands.py

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+import click
+
+
+@click.command()
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def add(a, b):
+    click.echo(a + b)
+
+
+@click.command()
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def sub(a, b):
+    click.echo(a - b)
+
+
+@click.command()
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def mul(a, b):
+    click.echo(a * b)
+
+
+@click.command()
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def div(a, b):
+    click.echo(a / b)

python-click/calc_v3/calc.py

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+import click
+import commands
+
+
+@click.group()
+def cli():
+    pass
+
+
+cli.add_command(commands.add)
+cli.add_command(commands.sub)
+cli.add_command(commands.mul)
+cli.add_command(commands.div)
+
+if __name__ == "__main__":
+    cli()

python-click/calc_v3/commands.py

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+import click
+
+
+@click.command(help="Add two numbers.")
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def add(a, b):
+    click.echo(a + b)
+
+
+@click.command(help="Subtract two numbers.")
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def sub(a, b):
+    click.echo(a - b)
+
+
+@click.command(help="Multiply two numbers.")
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def mul(a, b):
+    click.echo(a * b)
+
+
+@click.command(help="Divide two numbers.")
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def div(a, b):
+    click.echo(a / b)

python-click/calc_v4/README.md

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+# calc
+
+Calc is a CLI application that performs arithmetic operations. It takes a subcommand representing the target operation and two numeric arguments. It returns the result of performing the target operations between the two input values.
+
+## Installation
+
+1. Create a Python virtual environment
+
+```sh
+$ python -m venv ./venv
+$ source venv/bin/activate
+(venv) $
+```
+
+2. Install calc in editable mode
+
+```sh
+(venv) $ python -m pip install -e .
+```
+
+## Run the Project
+
+```sh
+(venv) $ calc add 3 4
+7.0
+
+(venv) $ calc sub 3 4
+-1.0
+
+(venv) $ calc mul 3 4
+12.0
+
+(venv) $ calc div 3 4
+0.75
+```
+
+## Features
+
+Calc currently provides the following options:
+
+- `add` takes two numbers and adds them together.
+- `sub` takes two numbers and subtracts them.
+- `mul` takes two numbers and multiplies them.
+- `div` takes two numbers and divides them.
+
+## About the Author
+
+Leodanis Pozo Ramos - Email: [email protected]
+
+## License
+
+Distributed under the MIT license. See `LICENSE` in the root directory of this `materials` repo for more information.

python-click/calc_v4/calc/__main__.py

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+import click
+
+from . import commands
+
+
+@click.group()
+def cli():
+    pass
+
+
+cli.add_command(commands.add)
+cli.add_command(commands.sub)
+cli.add_command(commands.mul)
+cli.add_command(commands.div)

python-click/calc_v4/calc/commands.py

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+import click
+
+
+@click.command(help="Add two numbers.")
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def add(a, b):
+    click.echo(a + b)
+
+
+@click.command(help="Subtract two numbers.")
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def sub(a, b):
+    click.echo(a - b)
+
+
+@click.command(help="Multiply two numbers.")
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def mul(a, b):
+    click.echo(a * b)
+
+
+@click.command(help="Divide two numbers.")
+@click.argument("a", type=click.FLOAT)
+@click.argument("b", type=click.FLOAT)
+def div(a, b):
+    click.echo(a / b)

python-click/calc_v4/pyproject.toml

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+[build-system]
+requires = ["setuptools>=65.5.0", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "calc"
+version = "0.1.0"
+description = "A CLI application that performs arithmetic operations."
+readme = "README.md"
+authors = [{ name = "Real Python", email = "[email protected]" }]
+dependencies = [
+    "click >= 8.1.3",
+]
+
+[project.scripts]
+calc = "calc.__main__:cli"

python-click/cat.py

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+import click
+
+
+@click.command()
+@click.argument(
+    "files",
+    nargs=-1,
+    type=click.File("r"),
+)
+def cli(files):
+    for file in files:
+        click.echo(file.read().rstrip())
+
+
+if __name__ == "__main__":
+    cli()

python-click/days.py

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+import click
+
+
+@click.command()
+@click.option(
+    "--weekday",
+    type=click.Choice(
+        [
+            "Monday",
+            "Tuesday",
+            "Wednesday",
+            "Thursday",
+            "Friday",
+            "Saturday",
+            "Sunday",
+        ]
+    ),
+)
+def cli(weekday):
+    click.echo(f"Weekday: {weekday}")
+
+
+if __name__ == "__main__":
+    cli()

python-click/greet.py

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+import click
+
+
+@click.command()
+@click.option(
+    "--name",
+    multiple=True,
+)
+def cli(name):
+    for n in name:
+        click.echo(f"Hello, {n}!")
+
+
+if __name__ == "__main__":
+    cli()

python-click/hello.py

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+import click
+
+
+@click.command("hello")
+@click.version_option("0.1.0", prog_name="hello")
+def hello():
+    click.echo("Hello, World!")
+
+
+if __name__ == "__main__":
+    hello()

python-click/ls_v1.py

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+from pathlib import Path
+
+import click
+
+
+@click.command()
+@click.argument("path")
+def cli(path):
+    target_dir = Path(path)
+    if not target_dir.exists():
+        click.echo("The target directory doesn't exist")
+        raise SystemExit(1)
+
+    for entry in target_dir.iterdir():
+        click.echo(f"{entry.name:{len(entry.name) + 5}}", nl=False)
+
+    click.echo()
+
+
+if __name__ == "__main__":
+    cli()

python-click/ls_v2.py

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+from pathlib import Path
+
+import click
+
+
+@click.command()
+@click.argument(
+    "path",
+    type=click.Path(
+        exists=True,
+        file_okay=False,
+        readable=True,
+        path_type=Path,
+    ),
+)
+def cli(path):
+    for entry in path.iterdir():
+        click.echo(f"{entry.name:{len(entry.name) + 5}}", nl=False)
+
+    click.echo()
+
+
+if __name__ == "__main__":
+    cli()