Question

如何格式化符合PEP8的长断言语句？请忽略我的例子中人为的本性。

def afunc(some_param_name):
    assert isinstance(some_param_name, SomeClassName), 'some_param_name must be an instance of SomeClassName, silly goose!'

不能将它包装在括号中，因为这会改变assert语句的行为，因为它是关键字，而不是内置函数。

Answer 1

重要的是要记住，PEP8只是一个指导原则even states that there are times when the rules should be broken。

但最重要的是：知道何时不一致 - 有时风格指南并不适用。

考虑到这一点，我可能会用旧式续行来写这个：

def afunc(some_param_name):
    assert isinstance(some_param_name, SomeClassName), \ 
           'some_param_name must be an instance of SomeClassName, silly goose!'

如果这与你（或你的短信）并不合适，你可以随时做到：

def afunc(some_param_name):
    assert isinstance(some_param_name, SomeClassName), ( 
           'some_param_name must be an instance of SomeClassName, silly goose!')

甚至：

def afunc(some_param_name):
    assert isinstance(some_param_name, SomeClassName), ( 
           'some_param_name must be an instance of SomeClassName, '
           'silly goose!')

Answer 2

ERR_MESSAGE_01 = '''
Some really long error message
'''

assert condition(a,b), ERR_MESSAGE_01

我是怎么做的......而且我觉得这很合适......

Answer 3

值得注意的是，可以用括号括起来，而不是用你想的方式。

assert isinstance(some_param_name, 
                  SomeClassName), ('some_param_name must be an instance of '
                                   'SomeClassName, silly goose!')

但是，我不认为它特别易读。在某些情况下，它可能是正确的选择。

Answer 4

def afunc(some_param_name):
    assert (isinstance(some_param_name, SomeClassName)
            ), 'some_param_name must be an instance of SomeClassName, silly goose!'

这样就可以在不破坏断言行为的情况下，从PEP 8推荐的括号中获得隐含的行继续。

可替换地：

def afunc(some_param_name):
    assert isinstance(some_param_name, SomeClassName), (
           'some_param_name must be an instance of SomeClassName, silly goose!')

Answer 5

在Maximum Line Length部分结尾的pep8中对此进行了描述。

反斜杠有时仍然合适。例如，[...]另一种情况是使用assert语句。

因此，建议使用pep8作为第一个示例，例如：

def afunc(some_param_name):
    assert isinstance(some_param_name, SomeClassName), \ 
           'some_param_name must be an instance of SomeClassName, silly goose!'

如何格式化符合PEP8的python断言语句？

5 个答案: