python - 如何阻止方法内部的警告

Question

所以我使用的是来自第三方库的 method_x，每次我使用它时都会打印一条警告。因为我正在编写一些旨在从 cli 获取用户输入的代码，所以我想阻止这种烦人的打印。

import module_x

module_x.method_x() # Has expected behaviour but prints an annoying warning

我可以做些什么来阻止函数内的所有打印语句吗？也许用某些东西包装方法或暂时禁用标准输出？

编辑:我最终使用了日志记录模块的一种方法，该方法捕获警告并将它们重定向到日志文件。这是我制作的装饰器:

logging.basicConfig(filename='log/log', level=logging.WARNING)

class redirect_warnings_to_log(object):
    def __init__(self, f):
        self.f = f

    def __call__(self, args):
            logging.captureWarnings(True)
            self.f(args)
            logging.captureWarnings(False)

这是打印警告的修饰方法:

@redirect_warnings_to_log
def tweet(message):
    twt = api.PostUpdate(message)

Answer 1

正如问题所说-

I'm using method_x from a third party library which prints a warning every time I use it.

如果 method_x 使用 Python 的 warnings模块。然后你可以使用warnings.catch_warnings()连同 with 语句和 warnings.simplefilter()忽略警告，从而抑制警告。

例子-

>>> import warnings
>>> def f():
...     warnings.warn("Some warning!")
...
>>> f()
__main__:2: UserWarning: Some warning!
>>> with warnings.catch_warnings():
...     warnings.simplefilter("ignore")
...     f()
...

请注意，这只是暂时抑制警告，仅在 with block 内，在 if block 外使用 f() 时，它不会抑制那些警告.

---

来自 documentation -

While within the context manager all warnings will simply be ignored. This allows you to use known-deprecated code without having to see the warning while not suppressing the warning for other code that might not be aware of its use of deprecated code. Note: this can only be guaranteed in a single-threaded application. If two or more threads use the catch_warnings context manager at the same time, the behavior is undefined.