08_functions.py

# /// script
# requires-python = ">=3.10"
# dependencies = [
#     "marimo",
# ]
# ///

import marimo

__generated_with = "0.18.4"
app = marimo.App()


@app.cell(hide_code=True)
def _(mo):
    mo.md("""
    # Functions

    This tutorial is about an important topic: **functions.**

    A function is a reusable block of code, similar in spirit to a mathematical function. Each function has a **name**, and accepts some number of **arguments**. These arguments are used in the function "body" (its block of code), and each function can **return** values.

    **Example.** Below is an example function.
    """)
    return


@app.function
def greet(your_name):
    return f"Hello, {your_name}!"


@app.cell(hide_code=True)
def _(mo):
    mo.md(r"""
    The keyword `def` starts the function definition. The function's **name** is `greet`. It accepts one **argument** called `your_name`. It then creates a string and **returns** it.
    """)
    return


@app.cell(hide_code=True)
def _(mo):
    mo.md("""
    In the next cell, we **call** the function with a value and assign its return value to a variable.

    **Try it!** Try changing the input to the function.
    """)
    return


@app.cell
def _():
    greeting = greet(your_name="<your name here>")
    greeting
    return


@app.cell(hide_code=True)
def _(mo):
    mo.md("""
    **Why use functions?** Functions help you:

    - Break down complex problems
    - Create reusable code blocks
    - Improve code readability
    """)
    return


@app.cell(hide_code=True)
def _(mo):
    mo.md("""
    ## Default parameters
    Make your functions more flexible by providing default values.
    """)
    return


@app.function
def create_profile(name, age=18):
    return f"{name} is {age} years old"


@app.cell
def _():
    # Example usage
    example_name = "Alex"
    example_profile = create_profile(example_name)
    example_profile
    return


@app.cell(hide_code=True)
def _(mo):
    mo.md("""
    You can also create functions that reference variables outside the function body. This is called 'closing over' variables
    """)
    return


@app.cell
def _():
    base_multiplier = 2

    def multiplier(x):
        """
        Create a function that multiplies input by a base value.

        This demonstrates how functions can 'close over' 
        values from their surrounding scope.
        """
        return x * base_multiplier
    return (multiplier,)


@app.cell
def _(multiplier):
    print([multiplier(num) for num in [1, 2, 3]])
    return


@app.cell(hide_code=True)
def _(mo):
    mo.md("""
    ## Returning multiple values

    Functions can return multiple values: just separate the values to return by
    commas. Check out the next cell for an example.
    """)
    return


@app.function
def weather_analysis(temp):
    """
    Analyze weather based on temperature.

    Args:
        temp (float): Temperature in Celsius

    Returns:
        tuple: Weather status, recommendation, warning level
    """
    if temp <= 0:
        return "Freezing", "Wear heavy coat", "High"
    elif 0 < temp <= 15:
        return "Cold", "Layer up", "Medium"
    elif 15 < temp <= 25:
        return "Mild", "Comfortable clothing", "Low"
    else:
        return "Hot", "Stay hydrated", "High"


@app.cell
def _():
    temperature = 25
    return (temperature,)


@app.cell
def _(temperature):
    status, recommendation, warning_level = weather_analysis(temperature)
    status, recommendation, warning_level
    return


@app.cell
def _():
    import marimo as mo
    return (mo,)


if __name__ == "__main__":
    app.run()