Python——start

Getting started with Python

• 赋值变量

  字符串

  saying = "Hello World!"
  saying = 'Hello World!'

• 列表

  可变（可修改）

  bicycles = ['trek','redline','specialized']
  bicycles.append('ducati')  # 添加元素

• 元组

  不可变（不可修改）

  dimensions = (1920, 1080)
  print(dimensions[0])       # 正确访问
  # dimensions[0] = 1600     # 会引发TypeError

• if语句

  条件逻辑

  temperature = 25
  if temperature > 30:
  print("太热了")
  elif 20 <= temperature <= 30:
  print("宜人")
  else:
  print("凉爽")

• Python字典

  键值对集合

  user = {'name': 'John', 'age': 32}
  user['email'] = 'john@example.com'  # 添加新键
  print(user.get('country', '未知'))  # 安全获取值

• 输入&while

  交互式程序

  active = True
  while active:
  message = input("输入'quit'退出: ")
  if message == 'quit':
      active = False
  else:
      print(message)

• 函数

  代码复用

  def make_pizza(size, *toppings):
  """制作披萨的说明"""
  print(f"\n制作{size}寸披萨，配料：")
  for topping in toppings:
      print(f"- {topping}")
  make_pizza(12, 'mushroom', 'cheese')

• 类

  面向对象编程

  class Car:
  """汽车类示例"""
  def __init__(self, make, model):
      self.make = make
      self.model = model
      self.odometer = 0
  def update_odometer(self, mileage):
      if mileage >= self.odometer:
          self.odometer = mileage
  my_car = Car('Tesla', 'Model S')
  my_car.update_odometer(500)

• 文件

  数据持久化

  with open('diary.txt', 'w') as file:
  file.write("2025-1-25\n今天学会了Python！")
  with open('diary.txt') as file:
  content = file.readlines()
  print("日记内容:", content)

• 编写测试

  保证代码质量

  import unittest
  class TestCar(unittest.TestCase):
  def test_odometer(self):
      test_car = Car('Audi', 'A4')
      test_car.update_odometer(1000)
      self.assertEqual(test_car.odometer, 1000)
  if __name__ == '__main__':
  unittest.main()