python中is not
时间: 2024-04-03 22:34:25 浏览: 15
在Python中,is和is not是用于比较两个对象是否引用同一个内存地址的运算符。is表示两个对象引用同一个内存地址,而is not则表示两个对象引用不同的内存地址。例如,下面的代码:
```
a = [1, 2, 3]
b = [1, 2, 3]
if a is b:
print("a and b reference the same object")
else:
print("a and b reference different objects")
if a is not b:
print("a and b reference different objects")
else:
print("a and b reference the same object")
```
输出结果为:
```
a and b reference different objects
a and b reference different objects
```
因为a和b虽然内容相同,但是指向的内存地址不同,所以a is not b。
相关问题
python str is not callable
当出现"TypeError: 'str' object is not callable"错误时,通常是因为将字符串对象当作函数进行调用。在Python中,字符串是不可调用的,因此会引发此错误。
以下是解决此问题的一种方法:
```python
# 错误示例
str = "Hello"
print(str()) # TypeError: 'str' object is not callable
# 正确示例
str = "Hello"
print(str) # 输出:Hello
```
在错误示例中,将字符串对象`str`当作函数进行调用,导致出现了"TypeError: 'str' object is not callable"错误。而在正确示例中,直接打印字符串对象`str`,不进行调用操作,因此不会出现错误。
python xlsx is not sypported
I'm sorry, I'm not sure what you mean by "python xlsx is not supported". Could you please provide more context or clarify your question? I'll do my best to help!