Python_basic

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def func(
    pos1,              # 位置参数
    pos2,              # 位置参数
    pos3: int = 10,    # 带默认值的参数
    *args,             # 可变位置参数
    kw1,               # 关键字参数
    kw2: str = "test", # 带默认值的关键字参数
    **kwargs           # 可变关键字参数
):
    pass

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class Student:

    def __init__(self, name: str, age: int):
        self.name = name
        self.age = age
        
    @classmethod
    def from_dict(cls, data: dict):
        return cls(name=data["name"], age=data["age"])
    
    @staticmethod
    def is_valid_age(age: int) -> bool:
        return age > 0

    def say_hello(self):
        print(f"Hello, my name is {self.name} and I am {self.age} years old.")

    def __repr__(self):
        # eval(repr(obj))
        
        return f"Student(name={self.name!r}, age={self.age})"
        
        # dct = {
        #     "name": self.name,
        #     "age": self.age
        # }
        # return f"Student.from_dict({dct})"
    


dir(Student)  # To see all attributes and methods of the class
print(Student.__mro__)  # Output: (<class '__main__.Student'>, <class 'object'>)

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import datetime

now = datetime.datetime.now()
print(f"Current time: {now}")  # 使用 str()
print(f"Current time (repr): {now!r}")  # 使用 repr()

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from .utils.helpers import (
    format_datetime,
    calculate_price,
    generate_order_number,
)

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try:
    1/0
except Exception as e:
    print(e)
    raise e

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>>> a, b, *c = [1,2,3,3,4,5,6]
>>> a,b,c
(1, 2, [3, 3, 4, 5, 6])

>>> a, *b, c = [1,2,3,3,4,5,6]
>>> a,b,c
(1, [2, 3, 3, 4, 5], 6)