"""
Урок 29. Практикум 7 — весь код примеров одним файлом.

Источник: subjects/python-fundamentals/course/lessons/29-practice-7/examples.html
Файл собран автоматически (tools/build_lesson_examples.py): правьте страницу урока.
Запуск: python lesson-29.py
"""



# ====================================================================
# Пример 1. Безопасный поиск через index()
# ====================================================================
# 01_safe_index.py
products = ["Bread", "Butter", "Cheese", "Milk", "Eggs"]
target = "Milk"
if target in products:
    print(products.index(target) + 1)
else:
    print(f"Товар {target} отсутствует")
# 4

missing = "Juice"
if missing in products:
    print(products.index(missing) + 1)
else:
    print(f"Товар {missing} отсутствует")
# Товар Juice отсутствует

try:
    products.index("Juice")
except ValueError as error:
    print("ValueError:", error)
# ValueError: 'Juice' is not in list


# ====================================================================
# Пример 2. Уникальные слова без учёта регистра
# ====================================================================
# 02_unique_words.py
text = "Python is a great language. Python is popular and Python is powerful."
words = [word.strip(".").lower() for word in text.split()]
unique_sorted = sorted(set(words))
print("Всего слов:", len(words), "уникальных:", len(unique_sorted))
print(unique_sorted)
# Всего слов: 12 уникальных: 8
# ['a', 'and', 'great', 'is', 'language', 'popular', 'powerful', 'python']


# ====================================================================
# Пример 3. Элемент по критерию: max(key=len)
# ====================================================================
# 03_max_key.py
sentence = "Programming in Python is both fun and educational"
words = sentence.split()
longest = max(words, key=len)
print("Самое длинное слово:", longest, "длина:", len(longest))
# Самое длинное слово: Programming длина: 11


# ====================================================================
# Пример 4. Перегруппировка списка с сохранением порядка
# ====================================================================
# 04_stable_partition.py
numbers = [4, 7, 1, 6, 3, 8, 2]
big = [n for n in numbers if n >= 5]
small = [n for n in numbers if n < 5]
print("Было:", numbers)
print("Стало:", big + small)
# Было: [4, 7, 1, 6, 3, 8, 2]
# Стало: [7, 6, 8, 4, 1, 3, 2]


# ====================================================================
# Пример 5. Уникальные суммы пар чисел
# ====================================================================
# 05_pair_sums.py
values = [3, 5, 9, 3]
pair_sums = set()
for i in range(len(values)):
    for j in range(i + 1, len(values)):
        pair_sums.add(values[i] + values[j])
print(sorted(pair_sums, reverse=True))
# [14, 12, 8, 6]


# ====================================================================
# Пример 6. Удаление элементов из списка — только с конца
# ====================================================================
# 06_delete_from_end.py
transactions = [(100, -50, -30), (-200, 100, 50), (-50, -50)]
print("Суммы:", [sum(t) for t in transactions])
# Суммы: [20, -50, -100]

correct = transactions.copy()
for index in range(len(correct) - 1, -1, -1):
    if sum(correct[index]) < 0:
        del correct[index]
print("После очистки:", correct)
# После очистки: [(100, -50, -30)]


# ====================================================================
# Пример 7. Список внутри кортежа остаётся изменяемым
# ====================================================================
# 07_mutable_in_tuple.py
employees = [
    ("Alice", ["Review documents", "Call clients"]),
    ("Bob", ["Check emails"]),
]
name, tasks = employees[0]
tasks.append("Prepare presentation")
print(employees)
# [('Alice', ['Review documents', 'Call clients', 'Prepare presentation']), ('Bob', ['Check emails'])]

try:
    employees[0][0] = "Carol"
except TypeError as error:
    print("TypeError:", error)
# TypeError: 'tuple' object does not support item assignment


# ====================================================================
# Пример 8. Проверка подпоследовательности указателем
# ====================================================================
# 08_subsequence.py
digits = ["3", "6", "3", "2", "9", "3", "9", "4", "3", "9", "0"]

sequence = "943"
position = 0
for digit in digits:
    if position < len(sequence) and digit == sequence[position]:
        position += 1
print("Последовательность найдена:", position == len(sequence))
# Последовательность найдена: True

sequence2 = "900"   # в digits только один символ "0" (в самом конце) — второй "0" найти негде
position2 = 0
for digit in digits:
    if position2 < len(sequence2) and digit == sequence2[position2]:
        position2 += 1
print("Последовательность найдена:", position2 == len(sequence2))
# Последовательность найдена: False


# ====================================================================
# Пример 9. Коды символов: ord(), chr() и сдвиг
# ====================================================================
# 09_ascii_cipher.py
shift = 3
message = "Python"
encoded = [ord(char) + shift for char in message]
print("Коды со сдвигом:", encoded)
# Коды со сдвигом: [83, 124, 119, 107, 114, 113]

decoded = "".join(chr(code - shift) for code in encoded)
print("Расшифровано:", decoded)
# Расшифровано: Python