Python 中的跨平台/dev/null

我使用以下代码在 Linux/OSX 上隐藏一个 Python 库的 stderr，我不能控制它默认写入 stderr:

f = open("/dev/null","w")
zookeeper.set_log_stream(f)

对于/dev/null，是否有一种简单的跨平台替代方案？理想情况下，它不会消耗内存，因为这是一个长时间运行的进程。

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小开
最佳答案

How about os.devnull ?

import os
f = open(os.devnull,"w")
zookeeper.set_log_stream(f)
小开 
>>> import os
>>> os.devnull
'nul'
小开 
class Devnull(object):
def write(self, *_): pass


zookeeper.set_log_stream(Devnull())

Opening os.devnull is fine too of course, but this way every output operation occurs (as a noop) "in process" -- no context switch to the OS and back, and also no buffering (while some buffering is normally used by an open) and thus even less memory consumption.

小开

Create your own file-like object which doesn't do anything?

class FakeSink(object):
def write(self, *args):
pass
def writelines(self, *args):
pass
def close(self, *args):
pass
小开

Cheap solution warning!

class DevNull():
def __init__(self, *args):
self.closed = False
self.mode = "w"
self.name = "<null>"
self.encoding = None
self.errors = None
self.newlines = None
self.softspace = 0
def close(self):
self.closed == True
@open_files_only
def flush(self):
pass
@open_files_only
def next(self):
raise IOError("Invalid operation")
@open_files_only
def read(size = 0):
raise IOError("Invalid operation")
@open_files_only
def readline(self):
raise IOError("Invalid operation")
@open_files_only
def readlines(self):
raise IOError("Invalid operation")
@open_files_only
def xreadlines(self):
raise IOError("Invalid operation")
@open_files_only
def seek(self):
raise IOError("Invalid operation")
@open_files_only
def tell(self):
return 0
@open_files_only
def truncate(self):
pass
@open_files_only
def write(self):
pass
@open_files_only
def writelines(self):
pass


def open_files_only(fun):
def wrapper(self, *args):
if self.closed:
raise IOError("File is closed")
else:
fun(self, *args)
return wrapper

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