ifvariableisNone:print("变量为空") 1. 2. 在上面的代码示例中,我们使用is关键字来判断变量variable是否为空。如果条件成立,即变量等于None,则打印出"变量为空"。 完整示例代码 下面是完整的示例代码,展示了如何实现“python if 条件等于null”: # 定义变量variable=None# 条件判断ifvariablei
type(variable) 返回输入的变量类型,如果变量是字典就返回字典类型 dict.clear() 删除字典内所有元素 dict.copy() 返回一个字典的浅复制 dict.haskey(key) 如果键在字典 dict 里返回 True,否则返回 False dict.get(key) 返回指定键的值 dict.keys() 以列表返回一个字典所有的键 dict.values() 以列表返回字典...
TypeError Raised when a function or operation is applied to an object of an incorrect type. UnboundLocalError Raised when a reference is made to a local variable in a function or method, but no value has been bound to that variable. UnicodeError Raised when a Unicode-related encoding or decod...
这里我们简单地打印出"Variable is None."表示变量为空值。 4. 处理非空值情况 如果变量不为空值,我们可以在if语句块内处理非空值情况。 print("Variable is not None.") 1. 这里我们简单地打印出"Variable is not None."表示变量不为空值。 完整代码示例 variable=NoneifvariableisnotNone:print("Variable ...
In Python, Check if Variable Is None and Check if Variable Is null have same solutions as meaning of both queries is same. 1. Introduction In Python Programming, checking when a variable is None(Python equivalent of null or nil in other languages) is a common task, particularly in functions...
print("This variable is None.")```这里有一个新一代的博客平台【WRITE- BUG数字空间】，它是一款...
d={'name':'jason','age':20}d['name']'jason'd['location']Traceback(most recent call last):File"<stdin>",line1,in<module>KeyError:'location'd={'name':'jason','age':20}d.get('name')'jason'd.get('location','null')'null ...
将分类变量转换为数值变量 一些机器学习模型要求变量采用数值格式。这需要先将分类变量转换为数值变量。同时，你也可以保留分类变量，以便进行数据可视化。def convert_cat2num(df):# Convert categorical variable to numerical variable num_encode = {'col_1' : {'YES':1, 'NO':0}, 'col_2' : {'...
in the same line, the Python interpreter creates a new object, then references the second variable at the same time. If you do it on separate lines, it doesn't "know" that there's already "wtf!" as an object (because "wtf!" is not implicitly interned as per the facts mentioned abov...
the ctypes private copy of the system errno variable is exchanged with the real errno value before and after the call; use_last_error does the same for the Windows error code.ctypes.WINFUNCTYPE(restype, *argtypes, use_errno=False, use_last_error=False)Windows only: The returned function ...