Merge pull request #668 from realpython/python-function

Sample code for the article on functions

Author: brendaweles

python-function/README.md

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+# Defining Your Own Python Function
+
+This folder provides the code examples for the Real Python tutorial [Defining Your Own Python Function](https://realpython.com/defining-your-own-python-function/).

python-function/average.py

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+def cumulative_average(numbers):
+    total = 0
+    for items, number in enumerate(numbers, 1):
+        total += number
+        yield total / items
+
+
+values = [5, 3, 8, 2, 5]  # Simulates a large data set
+
+for cum_average in cumulative_average(values):
+    print(f"Cumulative average: {cum_average:.2f}")
+
+
+def average(*args):
+    return sum(args) / len(args)
+
+
+print(average(1, 2, 3, 4, 5, 6))
+print(average(1, 2, 3, 4, 5, 6, 7))
+print(average(1, 2, 3, 4, 5, 6, 7, 8))

python-function/calculate.py

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+def calculate(x, y, *, operator):
+    if operator == "+":
+        return x + y
+    elif operator == "-":
+        return x - y
+    elif operator == "*":
+        return x * y
+    elif operator == "/":
+        return x / y
+    else:
+        raise ValueError("invalid operator")
+
+
+calculate(3, 4, operator="+")
+calculate(3, 4, operator="-")
+calculate(3, 4, operator="*")
+calculate(3, 4, operator="/")

python-function/calculations.py

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+def add(a: int | float, b: int | float) -> int | float:
+    return a + b

python-function/closure.py

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+def function():
+    value = 42
+
+    def closure():
+        print(f"The value is: {value}!")
+
+    return closure
+
+
+reveal_number = function()
+reveal_number()

python-function/cost.py

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+def calculate_cost(item, quantity, price):
+    print(f"{quantity} {item} cost ${quantity * price:.2f}")
+
+
+print(calculate_cost("bananas", 6, 0.74))

python-function/double.py

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+def double(numbers):
+    for i, _ in enumerate(numbers):
+        numbers[i] *= 2
+
+
+numbers = [1, 2, 3, 4, 5]
+print(double(numbers))

python-function/format_name.py

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+def format_name(first_name, last_name, /, title=None):
+    full_name = f"{first_name} {last_name}"
+    if title is not None:
+        full_name = f"{title} {full_name}"
+    return full_name
+
+
+print(format_name("Jane", "Doe"))
+print(format_name("John", "Doe", title="Dr."))
+print(format_name("Linda", "Brown", "PhD."))

python-function/greeting.py

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+# def greet(name):
+#     print(f"Hello, {name}!")
+
+
+def greet(name, verbose=False):
+    if verbose:
+        print(f"Hello, {name}! Welcome to Real Python!")
+    else:
+        print(f"Hello, {name}!")
+
+
+greet("Pythonista", verbose=True)
+greet("Pythonista")

python-function/hypotenuse.py

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+def hypotenuse(a, b, /):
+    return (a**2 + b**2) ** 0.5