def query(self, condition=None): if condition: query_str = f"SELECT * FROM {self.table_name} WHERE {condition}" else: query_str = f"SELECT * FROM {self.table_name}" self.cursor.execute(query_str) return self.cursor.fetchall() 现在,UserDAO实例可以直接用来查询数据库: user_dao = User...
函数的作用 - 代码的坏味道 / 用函数封装功能模块 定义函数 - def语句 / 函数名 / 参数列表 / return语句 / 调用自定义函数 调用函数 - Python内置函数 / 导入模块和函数 函数的参数 - 默认参数 / 可变参数 / 关键字参数 / 命名关键字参数 函数的返回值 - 没有返回值 / 返回单个值 / 返回多个值 作用...
def __init__(self, name, age): self.name = name self.age = age def introduce(self): return f"My name is {self.name} and I am {self.age} years old." # 使用匿名函数 addition_lambda = lambda x, y: x + y result = addition_lambda(3, 5) print(result) # 输出: 81.2 设计模式...
Project: 《最新出炉》系列小成篇-Python+Playwright自动化测试-66 - 等待元素至指定状态'''#3.导入模块fromplaywright.sync_apiimportPlaywright, sync_playwright, expectdefrun(playwright: Playwright) ->None: browser= playwright.chromium.launch(headless=False) context=browser.new_context() page=context.new_...
message = args[0] else: self.message = None def __str__(self): print('calling str') if self.message: return 'MyCustomError, {0} '.format(self.message) else: return 'MyCustomError has been raised' 在文件当前位置进入交互模式,执行如下操作: >>> from customexception import * >>> ...
Let's take a simple example to begin with. We have a Point class which defines a method distance to calculate the distance from the origin. class Point(object): def __init__(self,x = 0,y = 0): self.x = x self.y = y def distance(self): """Find distance from origin""" ...
keyword.kwlist ['False','None','True','and','as','assert','break','class','continue','def','del','elif','else','except','finally','for','from','global','if','import','in','is','lambda','nonlocal','not','or','pass','raise','return','try','while','with','yield...
def __init__(self, iterable): self._balls = list(iterable) 这样可以使你的代码更灵活,因为list()构造函数处理任何适合内存的可迭代对象。如果参数不可迭代,调用将立即失败,并显示一个非常清晰的TypeError异常,就在对象初始化时。如果想更明确,可以用try/except包装list()调用以自定义错误消息——但我只会在...
classPoint:def__init__(self,x,y,z):self.move_to(x,y,z)defis_origin(self):returnself.x==self.y==self.z==0defmove_to(self,x,y,z):self.x,self.y,self.z=x,y,z We can make aninstanceof this class, by calling it. We can accessattributesand can callmethodson thisclass instance...
>>>#Definetwo functionswithonecalling the other>>>defcast_number(number_text,to_raise):...try:...int(number_text)...except:...print("Failed to cast")...ifto_raise:...print("Re-raise the exception")...raise...>>>defrun_cast_number(number_text,to_raise):...try:...cast_numbe...