Merge branch 'master' into python-repl-314

brendaweles · web-flow · commit f72327ba568a · 2025-09-04T17:43:30.000-06:00
diff --git a/how-to-drop-null-values-in-pandas/README.md b/how-to-drop-null-values-in-pandas/README.md
@@ -0,0 +1,25 @@
+# How to Drop Null Values in pandas
+
+The materials contained in this download are designed to complement the Real Python tutorial [How to Drop Null Values in pandas](https://realpython.com/how-to-drop-null-values-in-pandas/).
+
+Consider creating a [Python virtual environment](https://realpython.com/python-virtual-environments-a-primer/) before installing the dependencies:
+
+```shell
+$ python3 -m venv .venv/ --prompt pandas-nulls
+$ source .venv/bin/activate
+(pandas-nulls) $ python -m pip install -r requirements.txt
+```
+
+Your download bundle contains the following four files:
+
+1. `drop_null_rows.py`
+2. `drop_null_columns.py`
+3. `drop_a_subset.py`
+4. `exercise_solutions.py`
+
+The first three files contain the code from different tutorial sections, while the fourth contains the solutions to the exercise.
+
+There are also two data files containing the data used throughout the tutorial:
+
+1. `sales_data_with_missing_values.csv`
+2. `grades.csv`
diff --git a/how-to-drop-null-values-in-pandas/drop_a_subset.py b/how-to-drop-null-values-in-pandas/drop_a_subset.py
@@ -0,0 +1,14 @@
+import pandas as pd
+
+pd.set_option("display.max_columns", None)
+
+sales_data = pd.read_csv(
+    "sales_data_with_missing_values.csv",
+    parse_dates=["order_date"],
+    date_format="%d/%m/%Y",
+).convert_dtypes(dtype_backend="pyarrow")
+
+print(sales_data.dropna(axis=0, subset=(["discount", "sale_price"])))
+print(sales_data.dropna(how="all"))
+print(sales_data.dropna(thresh=5))
+print(sales_data.dropna(thresh=5, ignore_index=True))
diff --git a/how-to-drop-null-values-in-pandas/drop_null_columns.py b/how-to-drop-null-values-in-pandas/drop_null_columns.py
@@ -0,0 +1,9 @@
+import pandas as pd
+
+sales_data = pd.read_csv(
+    "sales_data_with_missing_values.csv",
+    parse_dates=["order_date"],
+    date_format="%d/%m/%Y",
+).convert_dtypes(dtype_backend="pyarrow")
+
+print(sales_data.dropna(axis="columns"))
diff --git a/how-to-drop-null-values-in-pandas/drop_null_rows.py b/how-to-drop-null-values-in-pandas/drop_null_rows.py
@@ -0,0 +1,19 @@
+import pandas as pd
+
+pd.set_option("display.max_columns", None)
+
+sales_data = pd.read_csv(
+    "sales_data_with_missing_values.csv",
+    parse_dates=["order_date"],
+    date_format="%d/%m/%Y",
+).convert_dtypes(dtype_backend="pyarrow")
+
+print(sales_data)
+print(sales_data.isna().sum())
+print(sales_data.dropna())
+
+clean_sales_data = sales_data.dropna()
+print(clean_sales_data)
+
+sales_data.dropna(inplace=True)
+print(sales_data)
diff --git a/how-to-drop-null-values-in-pandas/exercise_solutions.py b/how-to-drop-null-values-in-pandas/exercise_solutions.py
@@ -0,0 +1,20 @@
+import pandas as pd
+
+grades = pd.read_csv(
+    "grades.csv",
+).convert_dtypes(dtype_backend="pyarrow")
+
+# 1. Use `.dropna()` in such a way that it permanently drops the row in the dataframe containing only null values.
+grades.dropna(how="all", inplace=True)
+
+# 2. Display the rows for the exams that all students have completed.
+grades.dropna()
+
+# 3. Display any columns with no missing data.
+grades.dropna(axis=1)
+
+# 4. Display the exams sat by at least five students.
+grades.dropna(axis=0, thresh=6)  # Remember there are seven columns.
+
+# 5. Who else was in in every exam that both S2 and S4 sat?
+grades.dropna(subset=["S2", "S4"]).dropna(axis=1, ignore_index=True)
diff --git a/how-to-drop-null-values-in-pandas/grades.csv b/how-to-drop-null-values-in-pandas/grades.csv
@@ -0,0 +1,8 @@
+Subject,S1,S2,S3,S4,S5,S6
+math,18,,15,20,17,18
+science,26,35,19,,33,
+art,15,,9,17,18,14
+music,14,20,12,20,13,18
+history,18,19,,17,,18
+sport,20,17,20,17,18
+,,,,,
diff --git a/how-to-drop-null-values-in-pandas/requirements.txt b/how-to-drop-null-values-in-pandas/requirements.txt
@@ -0,0 +1,7 @@
+numpy==2.3.2
+pandas==2.3.2
+pyarrow==21.0.0
+python-dateutil==2.9.0.post0
+pytz==2025.2
+six==1.17.0
+tzdata==2025.2
diff --git a/how-to-drop-null-values-in-pandas/sales_data_with_missing_values.csv b/how-to-drop-null-values-in-pandas/sales_data_with_missing_values.csv
@@ -0,0 +1,12 @@
+order_number,order_date,customer_name,product_purchased,discount,sale_price
+,09/02/2025,Skipton Fealty,Chili Extra Virgin Olive Oil,TRUE,135.00
+70041,,Carmine Priestnall,,,150.00
+70042,09/02/2025,,Rosemary Olive Oil Candle,FALSE,78.00
+70043,10/02/2025,Lanni D'Ambrogi,,TRUE,19.50
+70044,10/02/2025,Tann Angear,Vanilla and Olive Oil Candle,,13.98
+70045,10/02/2025,Skipton Fealty,Basil Extra Virgin Olive Oil,TRUE,
+70046,11/02/2025,Far Pow,Chili Extra Virgin Olive Oil,FALSE,150.00
+70047,11/02/2025,Hill Group,Chili Extra Virgin Olive Oil,TRUE,135.00
+70048,11/02/2025,Devlin Nock,Lavender and Olive Oil Lotion,FALSE,39.96
+,,,,,
+70049,12/02/2025,Swift Inc,Garlic Extra Virgin Olive Oil,TRUE,936.00
diff --git a/python-docstrings/get_potter_books.py b/python-docstrings/get_potter_books.py
@@ -1,3 +1,3 @@
-from multi_line_docstring import get_harry_potter_books
+from multiline_docstring import get_harry_potter_books
 
 print(get_harry_potter_books.__doc__)
diff --git a/python-docstrings/google_style.py b/python-docstrings/google_style.py
@@ -4,7 +4,7 @@ def get_magic_items(user_id, include_potions=False):
 
     Args:
         user_id (int): The ID of the user whose items should be retrieved.
-        include_potions (bool, optional): Whether to include potions in the result.
+        include_potions (bool, optional): Whether to include potions.
 
     Returns:
         list[str]: A list of item names associated with the user.
diff --git a/python-docstrings/magic_spells.py b/python-docstrings/magic_spells.py
@@ -1,12 +1,12 @@
 def undo_spell(spell):
     """
-    Reverses characters in a spell incantation thereby undoing a spell.
+    Reverses characters in a spell incantation, thereby undoing a spell.
 
     Example:
     >>> undo_spell("Expelliarmus")
-    "sumraillepxE"
+    'sumraillepxE'
 
     >>> undo_spell("Lumos")
-    "somuL"
+    'somuL'
     """
     return spell[::-1]
diff --git a/python-docstrings/magical_characters.py b/python-docstrings/magical_characters.py
@@ -1,4 +1,4 @@
-"""A magical module for adding and listing magical characters."""
+"""A module for adding and listing magical characters."""
 
 
 def add_characters(magical_being):
diff --git a/python-docstrings/multiline_docstring.py b/python-docstrings/multiline_docstring.py
@@ -1,14 +1,12 @@
-def get_harry_potter_books(publication_year, book_name):
+def get_harry_potter_book(publication_year, title):
     """
     Retrieve a Harry Potter book by its publication year and name.
 
     Parameters:
     publication_year (int): The year the book was published.
-    book_name (str): The name of the book.
+    title (str): The title of the book.
 
     Returns:
     str: A sentence describing the book and its publication year.
     """
-    return (
-        f"The book {book_name} was published in the year {publication_year}."
-    )
+    return f"The book {title!r} was published in the year {publication_year}."
diff --git a/python-docstrings/navigation.py b/python-docstrings/navigation.py
@@ -1,5 +1,6 @@
 """
 This module provides tools for creating and managing magical maps.
+
 Example:
     from navigation import build_map
     build_map(["mandrake", "phoenix feather", "tree bark"], heat_level=3)
diff --git a/python-docstrings/one_line_docstring.py b/python-docstrings/one_line_docstring.py
@@ -2,6 +2,6 @@
 
 
 def picking_hat():
-    """Returns a random house name."""
+    """Return a random house name."""
     houses = ["Gryffindor", "Hufflepuff", "Ravenclaw", "Slytherin"]
     return random.choice(houses)
diff --git a/python-docstrings/reStructuredText.py b/python-docstrings/reStructuredText.py
diff --git a/python-ty/README.md b/python-ty/README.md
@@ -0,0 +1,3 @@
+# Astral's ty: A New Blazing-Fast Type Checker for Python
+
+This folder contains sample code for the Real Python tutorial [Astral's ty: A New Blazing-Fast Type Checker for Python](https://realpython.com/python-ty/).
diff --git a/python-ty/adder.py b/python-ty/adder.py
@@ -0,0 +1,28 @@
+# fmt:off
+
+import warnings
+
+type Number = int | float
+
+
+def new_adder(x: Number, y: Number) -> Number:
+    return x + y
+
+
+@warnings.deprecated("Use the new_adder() instead")
+def legacy_adder(x, y):
+    return x + y
+
+
+if __name__ == "__main__":
+    legacy_adder(  # ty: ignore
+        42,
+        555
+    )
+
+    legacy_adder(
+        42,
+        555
+    )  # ty: ignore
+
+    new_adder(a=42, b=555)  # ty: ignore[unknown-argument, missing-argument]
diff --git a/python-ty/cross_platform.py b/python-ty/cross_platform.py
@@ -0,0 +1,9 @@
+from sys import platform
+from typing import reveal_type
+
+if platform == "win32":
+    x = "Windows"
+else:
+    x = "macOS or Linux"
+
+reveal_type(x)
diff --git a/python-ty/python_version.py b/python-ty/python_version.py
@@ -0,0 +1,3 @@
+from typing import Literal
+
+type Size = Literal["S", "M", "L", "XL"]
diff --git a/what-does-arrow-mean-in-python/README.md b/what-does-arrow-mean-in-python/README.md
@@ -0,0 +1,3 @@
+# What Does -> Mean in Python Function Definitions?
+
+This folder provides the code examples for the Real Python tutorial [What Does -> Mean in Python Function Definitions?](https://realpython.com/what-does-arrow-mean-in-python/) 
diff --git a/what-does-arrow-mean-in-python/dictionary_return_type_example.py b/what-does-arrow-mean-in-python/dictionary_return_type_example.py
@@ -0,0 +1,11 @@
+def get_highest_stock_games(game_stock: dict[str, int]) -> dict[str, int]:
+    max_quantity = max(game_stock.values())
+    return {
+        game: quantity
+        for game, quantity in game_stock.items()
+        if quantity == max_quantity
+    }
+
+
+game_stock = {"Dragon Quest": 5, "Final Fantasy": 1, "Age of Empires": 5}
+print("Games with the highest stock:", get_highest_stock_games(game_stock))
diff --git a/what-does-arrow-mean-in-python/dynamic_variable_example.py b/what-does-arrow-mean-in-python/dynamic_variable_example.py
@@ -0,0 +1,5 @@
+my_number = 32
+print(f"{my_number = }")
+
+my_number = "32"
+print(f"{my_number = }")
diff --git a/what-does-arrow-mean-in-python/game_class_example.py b/what-does-arrow-mean-in-python/game_class_example.py
@@ -0,0 +1,14 @@
+class Game:
+    def __init__(self, name: str, genre: str, price: float) -> None:
+        self.name = name
+        self.genre = genre
+        self.price = price
+
+    def get_name(self) -> str:
+        return self.name
+
+    def get_genre(self) -> str:
+        return self.genre
+
+    def get_price(self) -> float:
+        return self.price
diff --git a/what-does-arrow-mean-in-python/mismatched_return_type_example.py b/what-does-arrow-mean-in-python/mismatched_return_type_example.py
@@ -0,0 +1,6 @@
+def get_number_of_titles(titles: list[str]) -> str:
+    return len(titles)
+
+
+games = ["Dragon Quest", "Final Fantasy", "Age of Empires"]
+print("Number of titles:", get_number_of_titles(games))
diff --git a/what-does-arrow-mean-in-python/none_return_type_hint_example.py b/what-does-arrow-mean-in-python/none_return_type_hint_example.py
@@ -0,0 +1,9 @@
+def find_keyword_in_titles(titles: list[str], keyword: str) -> None:
+    print("Titles that contain the keyword:", keyword)
+    for game_title in titles:
+        if keyword in game_title:
+            print(game_title)
+
+
+games = ["Dragon Quest", "Final Fantasy", "Age of Empires"]
+find_keyword_in_titles(games, "es")
diff --git a/what-does-arrow-mean-in-python/simple_type_hint_example.py b/what-does-arrow-mean-in-python/simple_type_hint_example.py
@@ -0,0 +1,6 @@
+def get_number_of_titles(titles: list[str]) -> int:
+    return len(titles)
+
+
+games = ["Dragon Quest", "Final Fantasy", "Age of Empires"]
+print("Number of titles:", get_number_of_titles(games))
diff --git a/what-does-arrow-mean-in-python/str_return_type_hint_example.py b/what-does-arrow-mean-in-python/str_return_type_hint_example.py
@@ -0,0 +1,9 @@
+import random
+
+
+def get_game_recommendation(titles: list[str]) -> str:
+    return random.choice(titles)
+
+
+games = ["Dragon Quest", "Final Fantasy", "Age of Empires"]
+print("Random recommendation:", get_game_recommendation(games))

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,3 @@`
`1`		`-from multi_line_docstring import get_harry_potter_books`
	`1`	`+from multiline_docstring import get_harry_potter_books`
`2`	`2`
`3`	`3`	`print(get_harry_potter_books.__doc__)`