Python基础课程

# 📦 Python 数据类型示例

# 整数 int
a = 42
print(f"整数: {a}, 类型: {type(a).__name__}")

# 浮点数 float
b = 3.14
print(f"浮点数: {b}, 类型: {type(b).__name__}")

# 字符串 str
s = "Hello Python"
print(f"字符串: {s}, 长度: {len(s)}")

# 布尔值 bool
flag = True
print(f"布尔值: {flag}, 类型: {type(flag).__name__}")

# 列表 list - 可变的有序集合
fruits = ["苹果", "香蕉", "草莓"]
print(f"列表: {fruits}")

# 字典 dict - 键值对集合
student = {"name": "冬怡", "age": 20}
print(f"字典: {student}")

# 元组 tuple - 不可变的有序集合
point = (10, 20)
print(f"元组: {point}")

# 集合 set - 无序不重复集合
unique_nums = {1, 2, 2, 3, 3, 3}
print(f"集合(自动去重): {unique_nums}")

# 类型转换
x = "123"
print(f"字符串 '{x}' 转整数: {int(x) + 1}")

# 运算符
print(f"10 + 3 = {10 + 3}")   # 加法
print(f"10 // 3 = {10 // 3}") # 整除
print(f"10 % 3 = {10 % 3}")   # 取余
print(f"2 ** 10 = {2 ** 10}") # 幂运算

# 🔀 条件语句与循环示例

# if-elif-else 条件判断
score = 85
if score >= 90:
    grade = "优秀 🌟"
elif score >= 80:
    grade = "良好 👍"
elif score >= 60:
    grade = "及格 ✅"
else:
    grade = "需要加油 💪"
print(f"成绩: {score}, 等级: {grade}")

# for 循环遍历
print("\n--- for 循环 ---")
fruits = ["苹果", "香蕉", "草莓", "芒果"]
for i, fruit in enumerate(fruits):
    print(f"  {i+1}. {fruit}")

# range() 生成序列
print("\n--- range() ---")
for i in range(1, 6):
    print(f"  {i} 的平方是 {i**2}")

# while 循环
print("\n--- while 循环 ---")
count = 1
while count <= 3:
    print(f"  第 {count} 次")
    count += 1

# break 和 continue
print("\n--- break/continue ---")
for i in range(1, 10):
    if i == 3:
        continue  # 跳过3
    if i == 7:
        break     # 到7停止
    print(f"  i = {i}")

# 列表推导式
squares = [x**2 for x in range(1, 8)]
print(f"\n1-7的平方: {squares}")

# ⚡ 函数定义示例

# 基本函数
def greet(name):
    return f"你好，{name}！欢迎学习Python 🐍"

print(greet("冬怡"))

# 默认参数
def power(base, exp=2):
    return base ** exp

print(f"3的平方: {power(3)}")
print(f"2的10次方: {power(2, 10)}")

# 关键字参数
def describe(name, age, city="广东"):
    return f"{name}, {age}岁, 来自{city}"

print(describe("冬怡", age=20))

# 可变参数 *args
def total(*numbers):
    return sum(numbers)

print(f"总和: {total(1, 2, 3, 4, 5)}")

# 可变关键字参数 **kwargs
def print_info(**info):
    for key, value in info.items():
        print(f"  {key}: {value}")

print("\n学生信息:")
print_info(name="冬怡", major="数据分析", year=2)

# lambda 表达式
square = lambda x: x ** 2
print(f"\n5的平方: {square(5)}")

# 高阶函数 map/filter
nums = [1, 2, 3, 4, 5]
squared = list(map(lambda x: x**2, nums))
evens = list(filter(lambda x: x % 2 == 0, nums))
print(f"平方: {squared}")
print(f"偶数: {evens}")