1
变量名 = 值

1
# print()的语法格式如下
2
print(*object, sep=' ', end='\n', file=None, flush=False)

1
5    # 十进制
2
0b101    # 二进制
3
0o5    # 八进制
4
0x5    # 十六进制

1
# 各函数的用法
2
num = 12
3
print(bin(num))    # 将十进制转换成为二进制

1
print(3.14e500)
2
# 结果为inf

1
complex_one = complex(3, 2)
2
print(complex_one)
3
# 输出结果：(3+2j)

1
one = 1 + 2j
2
print(one.real)    # 获取复数的实部
3
print(one.imag)    # 获取复数的虚部

1
x, y = 5, 3
2
print(x == y)  # False
3
print(x > y)   # True
4
print(x != y)  # True

1
a, b = 5, 10
2
print(a > 0 and b < 20)  # True
3
print(a > 10 or b < 20)  # True
4
print(not a > 10)        # True

1
x = 'python'
2
y = 'p'
3
print(y in x)      # 结果为 True
4
print(y not in x)  # 结果为 False
5

6
fruits = ['apple', 'banana', 'orange']
7
print('apple' in fruits)  # True

1
if 条件:
2
    # 条件为 True 时执行的代码

1
if 条件:
2
    # 条件为 True 时执行的代码
3
else:
4
    # 条件为 False 时执行的代码

1
if 条件 1:
2
    # 条件 1 为 True 时执行的代码
3
elif 条件 2:
4
    # 条件 2 为 True 时执行的代码
5
elif 条件 3:
6
    # 条件 3 为 True 时执行的代码
7
else:
8
    # 所有条件都为 False 时执行的代码

1
if 条件 1:
2
    if 条件 2:
3
        # 条件 1 和条件 2 都为 True 时执行的代码
4
    else:
5
        # 条件 1 为 True，条件 2 为 False 时执行的代码

1
# 基本语法
2
while 条件:
3
    # 循环体

1
# 示例：计算 1 到 100 的和
2
sum = 0
3
i = 1
4
while i <= 100:
5
    sum += i
6
    i += 1
7
print(f"1 到 100 的和为：{sum}")

1
# 基本语法
2
for 变量 in 序列:
3
    # 循环体

1
# 遍历列表
2
fruits = ["apple", "banana", "orange"]
3
for fruit in fruits:
4
    print(fruit)
5

6
# 使用 range() 函数
7
for i in range(5):  # 0 到 4
8
    print(i)
9

10
for i in range(1, 6):  # 1 到 5
11
    print(i)
12

13
for i in range(1, 10, 2):  # 1, 3, 5, 7, 9
14
    print(i)

1
for i in range(10):
2
    if i == 5:
3
        break
4
    print(i)  # 输出 0 到 4

1
for i in range(10):
2
    if i % 2 == 0:
3
        continue
4
    print(i)  # 输出 1, 3, 5, 7, 9

1
for i in range(10):
2
    if i == 5:
3
        pass  # 暂时不处理，后续补充
4
    print(i)

1
# 打印九九乘法表
2
for i in range(1, 10):
3
    for j in range(1, i + 1):
4
        print(f"{j}×{i}={i*j}", end="\t")
5
    print()

1
for i in range(5):
2
    print(i)
3
else:
4
    print("循环正常结束")
5

6
# 带 break 的情况
7
for i in range(5):
8
    if i == 3:
9
        break
10
    print(i)
11
else:
12
    print("这行不会输出，因为循环被 break 终止")

1
def describe_pet(animal_type, pet_name):
2
    print(f"I have a {animal_type}.")
3
    print(f"My {animal_type}'s name is {pet_name}.")
4

5
describe_pet("dog", "Harry")  # 位置参数

1
describe_pet(pet_name="Harry", animal_type="dog")  # 关键字参数

1
def describe_pet(pet_name, animal_type="dog"):
2
    print(f"I have a {animal_type}.")
3
    print(f"My {animal_type}'s name is {pet_name}.")
4

5
describe_pet("Harry")  # 使用默认值
6
describe_pet("Harry", "cat")  # 覆盖默认值

1
def make_pizza(*toppings):
2
    """接收任意数量的配料"""
3
    print("Making a pizza with the following toppings:")
4
    for topping in toppings:
5
        print(f"- {topping}")
6

7
make_pizza("pepperoni")
8
make_pizza("mushrooms", "green peppers", "extra cheese")

1
def build_profile(first, last, **user_info):
2
    """接收任意数量的关键字参数"""
3
    user_info["first_name"] = first
4
    user_info["last_name"] = last
5
    return user_info
6

7
user = build_profile("albert", "einstein", location="princeton", field="physics")
8
print(user)

1
# 创建空列表
2
list1 = []
3
list2 = list()
4

5
# 创建包含元素的列表
6
fruits = ["apple", "banana", "orange"]
7
numbers = [1, 2, 3, 4, 5]
8
mixed = [1, "hello", 3.14, True]

1
fruits = ["apple", "banana", "orange", "grape"]
2

3
print(fruits[0])     # apple
4
print(fruits[-1])    # grape（负数索引表示从末尾开始）
5
print(fruits[1:3])   # ["banana", "orange"]（切片）
6
print(fruits[:2])    # ["apple", "banana"]
7
print(fruits[2:])    # ["orange", "grape"]

1
fruits = ["apple", "banana", "orange"]
2

3
# 修改元素
4
fruits[1] = "blueberry"
5

6
# 添加元素
7
fruits.append("grape")        # 末尾添加
8
fruits.insert(1, "mango")     # 指定位置插入
9

10
# 删除元素
11
fruits.remove("apple")        # 删除指定值
12
del fruits[0]                 # 删除指定位置
13
last = fruits.pop()           # 删除并返回末尾元素
14
first = fruits.pop(0)         # 删除并返回指定位置元素

1
list1 = [1, 2, 3]
2
list2 = [4, 5, 6]
3

4
# 列表拼接
5
list3 = list1 + list2  # [1, 2, 3, 4, 5, 6]
6

7
# 列表重复
8
list4 = list1 * 3  # [1, 2, 3, 1, 2, 3, 1, 2, 3]
9

10
# 列表长度
11
length = len(list1)  # 3
12

13
# 成员检查
14
print(2 in list1)  # True

1
# 基本语法
2
squares = [x ** 2 for x in range(10)]
3
# [0, 1, 4, 9, 16, 25, 36, 49, 64, 81]
4

5
# 带条件
6
evens = [x for x in range(20) if x % 2 == 0]
7
# [0, 2, 4, 6, 8, 10, 12, 14, 16, 18]
8

9
# 嵌套循环
10
pairs = [(x, y) for x in range(3) for y in range(3)]
11
# [(0, 0), (0, 1), (0, 2), (1, 0), (1, 1), (1, 2), (2, 0), (2, 1), (2, 2)]

1
# 创建空元组
2
tuple1 = ()
3
tuple2 = tuple()
4

5
# 创建元组
6
colors = ("red", "green", "blue")
7
numbers = 1, 2, 3, 4, 5  # 可以省略括号
8

9
# 单元素元组（需要逗号）
10
single = (1,)

1
colors = ("red", "green", "blue")
2
print(colors[0])      # red
3
print(colors[-1])     # blue
4
print(colors[1:])     # ("green", "blue")

1
point = (10, 20)
2
x, y = point
3
print(x)  # 10
4
print(y)  # 20
5

6
# 交换变量
7
a, b = 1, 2
8
a, b = b, a
9
print(a, b)  # 2, 1

1
# 创建空字典
2
dict1 = {}
3
dict2 = dict()
4

5
# 创建字典
6
person = {"name": "张三", "age": 18, "city": "北京"}
7

8
# 使用 dict() 函数
9
person = dict(name="张三", age=18, city="北京")
10

11
# 使用键值对列表
12
person = dict([("name", "张三"), ("age", 18), ("city", "北京")])

1
person = {"name": "张三", "age": 18}
2

3
# 通过键访问
4
print(person["name"])  # 张三
5

6
# 使用 get() 方法（键不存在时返回 None 或默认值）
7
print(person.get("age"))  # 18
8
print(person.get("gender", "未知"))  # 未知

1
person = {"name": "张三", "age": 18}
2

3
# 添加或修改键值对
4
person["age"] = 19           # 修改
5
person["gender"] = "男"      # 添加
6

7
# 删除
8
del person["name"]           # 删除指定键
9
age = person.pop("age")      # 删除并返回值
10
last = person.popitem()      # 删除并返回最后一对
11

12
# 清空
13
person.clear()

1
person = {"name": "张三", "age": 18, "city": "北京"}
2

3
# 遍历键
4
for key in person.keys():
5
    print(key)
6

7
# 遍历值
8
for value in person.values():
9
    print(value)
10

11
# 遍历键值对
12
for key, value in person.items():
13
    print(f"{key}: {value}")

1
# 创建平方字典
2
squares = {x: x ** 2 for x in range(5)}
3
# {0: 0, 1: 1, 2: 4, 3: 9, 4: 16}
4

5
# 带条件
6
even_squares = {x: x ** 2 for x in range(10) if x % 2 == 0}
7
# {0: 0, 2: 4, 4: 16, 6: 36, 8: 64}

1
# 创建空集合（注意：{} 创建的是空字典）
2
set1 = set()
3

4
# 创建集合
5
fruits = {"apple", "banana", "orange"}
6
numbers = set([1, 2, 3, 4, 5])

1
set1 = {1, 2, 3, 4, 5}
2
set2 = {4, 5, 6, 7, 8}
3

4
# 并集
5
union = set1 | set2  # {1, 2, 3, 4, 5, 6, 7, 8}
6

7
# 交集
8
intersection = set1 & set2  # {4, 5}
9

10
# 差集
11
difference = set1 - set2  # {1, 2, 3}
12

13
# 对称差集
14
symmetric_difference = set1 ^ set2  # {1, 2, 3, 6, 7, 8}

1
fruits = {"apple", "banana", "orange"}
2

3
# 添加
4
fruits.add("grape")           # 添加元素
5
fruits.update(["mango", "pear"])  # 添加多个元素
6

7
# 删除
8
fruits.remove("apple")        # 删除元素（不存在会报错）
9
fruits.discard("banana")      # 删除元素（不存在不报错）
10
last = fruits.pop()           # 随机删除并返回元素
11

12
# 清空
13
fruits.clear()