根据类别而非消息在warnings.simple_filter()过滤器中指定消息

时间:2019-02-06 13:15:22

标签: python warnings

在Python2中导入our_library时,我们对其进行了编码,以引发一次DeprecationWarning。这是代表代码。

our_library / 初始化 .py

def _py2_deprecation_warning():
    py2_warning = ('Python2 support is deprecated and will be removed in '
                   'a future release. Consider switching to Python3.')
    warnings.filterwarnings('once', message=py2_warning)
    warnings.warn(message=py2_warning,
                  category=DeprecationWarning,
                  stacklevel=3,
                  )


def _python_deprecation_warnings():
    if sys.version_info.major == 2:
        _py2_deprecation_warning()


_python_deprecation_warnings()

我们在our_library中的函数中弃用了参数。这是代表代码:

our_library / some_module.py

def some_function(new_param, deprecated_param):
  if deprecated_param:
      param_deprecation_msg = (
          'The parameter "{}" will be removed in a future version of Nilearn.'
          'Please use the parameter "{}" instead.'.format(deprecated_param,
                                                          new_param,
                                                          )
      )
      warnings.warn(category=DeprecationWarning,
                    message=param_deprecation_msg,
                    stacklevel=3)

然后,当我们导入库并调用该函数时,如下所示:

calling_script.py

from our_library.some_module import some_function

some_function(deprecated_param)

我们获得了Python2 DeprecationWarning,但没有参数DeprecationWarning。

DeprecationWarning: Python2 support is deprecated and will be removed in a future release. Consider switching to Python3. 
 _python_deprecation_warnings()

现在知道我可以使用with warnings.catch_warnings():resetwarnings()解决此问题。但是,我认为在Python2警告中明确指定消息会阻止为其他DeprecationWarnings设置'once过滤器。

但事实并非如此吗?这是为什么?如何在不使用CatchWarnings或重置警告的情况下使现有代码正常工作?

如果我将参数警告更改为FutureWarning,则可以看到。 为什么第一个simplefilter会基于类别而不是消息来阻止所有弃用消息?

更新: with warnings.catch_warnings():似乎也不起作用。

def _py2_deprecation_warning():
    py2_warning = ('Python2 support is deprecated and will be removed in '
                   'a future release. Consider switching to Python3.')
    with warnings.catch_warnings():
        warnings.filterwarnings('once', message=py2_warning)
        warnings.warn(message=py2_warning,
                      category=DeprecationWarning,
                      stacklevel=3,
                      )

1 个答案:

答案 0 :(得分:0)

没关系,我已经忘记了deprecation不会显示DeprecationWarnings。必须将它们专门设置为显示,这在这里我还没有做。