python中assert

Python断言关键字 (Python assert keyword)

assert is a keyword (case-sensitive) in python, it is used to debug the code. Generally, it can be used to test a condition – if a condition returns False – it returns an Assertion Error (AssertionError).

assert是python中的一个关键字(区分大小写)，用于调试代码。 通常，它可以用于测试条件-如果条件返回False-则返回断言错误(AssertionError) 。

Syntax of assert keyword

assert关键字的语法

    assert statement

Example:

例：

    Input:
num = 10
# assert statement
assert num==20
Output:
assert num==20
AssertionError

断言关键字的Python示例 (Python examples of assert keyword)

Example 1: Test a False result

示例1：测试错误的结果

# python code to demonstrate example of 
# assert statement 
num = 10    # number
# assert statements
# nothing will happed as the condition is true
assert num==10
#AssertionError will generate as the condition is false
assert num==20

Output

输出量

Traceback (most recent call last):
File "/home/main.py", line 12, in <module>
assert num==20
AssertionError

Example 2: Test a False result and return a customize message

示例2：测试错误结果并返回自定义消息

# python code to demonstrate example of 
# assert statement 
num = 10    # number
# assert statements
# nothing will happed as the condition is true
assert num==10
#AssertionError will generate as the condition is false
assert num==20, "There is an error with num's value"

Output

输出量

Traceback (most recent call last):
File "/home/main.py", line 12, in <module>
assert num==20, "There is an error with num's value"
AssertionError: There is an error with num's value

翻译自: https://www.includehelp.com/python/assert-keyword-with-example.aspx

python中assert