assert的基本语法是：
"assert" expression1 ["," expression2]
expression1用于判断生成布尔值，当expression1为假的时候，则抛出异常，[]中的内容可选，即用户可以选择异常的提示值：
|
1
2
3
4
5
6
7
8
9
10
11
|
>>>a=23
>>>assert a==23
>>>a=a-1
>>>assert a==23
Traceback (most recent call last): File "<stdin>", line 1, in <module>
AssertionError>>>assert a==23 , "error1"
Traceback (most recent call last): File "<stdin>", line 1, in <module>
AssertionError: error1 |