# 定义一个对象classMyClass:def__init__(self):self.attr='Hello'obj=MyClass()# 方法一:使用is not NoneifobjisnotNone:print('Object exists')else:print('Object does not exist')# 方法二:使用hasattrifhasattr(obj,'attr'):print('Attribute exists')else:print('Attribute does not exist') 1. ...
class WSGIRequest(http.HttpRequest): def __init__(self, environ): script_name = get_script_name(environ) path_info = get_path_info(environ) if not path_info: # Sometimes PATH_INFO exists, but is empty (e.g. accessing # the SCRIPT_NAME URL without a trailing slash). We really need...
letters = ['A', 'B', 'C'] if 'A' in letters: print('A' + ' exists') if 'h' not in letters: print('h' + ' not exists') # A exists # h not exists A exists h not exists 【例子】比较的两个变量均指向不可变类型。
为了做到这一点,将前面提到的类定义保存在一个名为first_class.py的文件中,然后运行python -i first_class.py命令。-i参数告诉 Python运行代码然后转到交互式解释器。以下解释器会话演示了与这个类的基本交互: >>>a = MyFirstClass()>>>b = MyFirstClass()>>>print(a) <__main__.MyFirstClassobjectat0xb7...
The Context class has the following string attributes:Expand table AttributeDescription function_directory The directory in which the function is running. function_name The name of the function. invocation_id The ID of the current function invocation. thread_local_storage The thread local storage of...
getattr(object, name[, default])#object -- 对象#name -- 字符串,对象属性#default -- 默认返回值,如果不提供该参数,在没有对应属性时,将触发 AttributeError globals():以字典类型返回当前位置的全部全局变量 hasattr():用于判断对象是否包含对应的属性,e.g: ...
[] processed = set() names = dir(object) # 使用dir方法拿到全部的属性 # :dd any DynamicClassAttributes to the list of names if object is a class; # this may result in duplicate entries if, for example, a virtual # attribute with the same name as a DynamicClassAttribute exists try: ...
[:port] # http://hostname[:port] # 2) Do not add a trailing slash at the end of file server path. FILE_SERVER = 'sftp://sftpuser:Pwd123@10.1.3.2' # Remote file paths: # 1) The path may include directory name and file name. # 2) If file name is not specified, indicate ...
[col*64+20, row*64+20] if location not in locations: locations.append(location) attribute = random.choice(list(cfg.OBSTACLE_PATHS.keys())) img_path = cfg.OBSTACLE_PATHS[attribute] obstacle = ObstacleClass(img_path, location, attribute) obstacles.add(obstacle) return obstacles '''合并障碍物...
If given, doc will be the docstring of the property attribute. Otherwise, the property will copy fget‘s docstring (if it exists). This makes it possible to create read-only properties easily using property() as a decorator。 The @property decorator turns the voltage() method into a “gett...