Pythonを学ぶ際に最低限知っておくべき文法

x = 10        # 整数型
name = "John" # 文字列型
price = 9.99  # 浮動小数点型
is_active = True # 論理型

numbers = [1, 2, 3, 4, 5]
names = ["Alice", "Bob", "Charlie"]

person = {"name": "John", "age": 30, "city": "New York"}

age = 18
if age >= 18:
    print("You are an adult.")
elif age > 12:
    print("You are a teenager.")
else:
    print("You are a child.")

for i in range(5):
    print(i)

for name in names:
    print(name)

count = 0
while count < 5:
    print(count)
    count += 1

def greet(name):
    return f"Hello, {name}!"

print(greet("Alice"))

import math
print(math.sqrt(16)) # 4.0

try:
    result = 10 / 0
except ZeroDivisionError:
    print("You can't divide by zero!")

squares = [x**2 for x in range(10)]

# 1. 変数とデータ型
name = input("What is your name? ")  # 文字列型
age = int(input("How old are you? "))  # 整数型にキャスト

# 2. リストと辞書
hobbies = ["reading", "sports", "music"]  # リスト
person = {"name": name, "age": age, "hobbies": hobbies}  # 辞書

# 3. 条件分岐
if person["age"] >= 18:
    print(f"Hello, {person['name']}! You are an adult.")
elif person["age"] > 12:
    print(f"Hello, {person['name']}! You are a teenager.")
else:
    print(f"Hello, {person['name']}! You are a child.")

# 4. ループ
print("Your hobbies are:")
for hobby in person["hobbies"]:  # リスト内の趣味を出力
    print(f"- {hobby}")

# 5. 関数
def calculate_square(number):
    return number ** 2

numbers = [1, 2, 3, 4, 5]
squares = [calculate_square(n) for n in numbers]  # リスト内包表記で計算
print("The squares of the numbers are:", squares)

# 6. モジュールのインポート
import math

# 平方根の計算をする関数を定義
def print_square_roots(numbers):
    for number in numbers:
        print(f"The square root of {number} is {math.sqrt(number)}")

print_square_roots(numbers)

# 7. 例外処理
try:
    division_result = 10 / 0
except ZeroDivisionError:
    print("You can't divide by zero!")

# 8. リスト内包表記
even_numbers = [x for x in range(20) if x % 2 == 0]
print("Even numbers between 0 and 20:", even_numbers)