根据这个答案:https://stackoverflow.com/a/5916874/1060344，这是我在我的一个项目中使用的另一种方法。无论你用什么替换sys。Stderr或sys。stderr/ Stdout被用在一些不受你控制的库中，你必须确保替换符合文件接口，特别是当你这样做的时候。该库可能正在使用文件对象的其他方法。

以这种方式检查，我仍然让所有内容都执行stderr/stdout(或任何文件)，并使用Python的日志记录功能将消息发送到日志文件(但你真的可以用它做任何事情):

class FileToLogInterface(file):
    '''
    Interface to make sure that everytime anything is written to stderr, it is
    also forwarded to a file.
    '''

    def __init__(self, *args, **kwargs):
        if 'cfg' not in kwargs:
            raise TypeError('argument cfg is required.')
        else:
            if not isinstance(kwargs['cfg'], config.Config):
                raise TypeError(
                    'argument cfg should be a valid '
                    'PostSegmentation configuration object i.e. '
                    'postsegmentation.config.Config')
        self._cfg = kwargs['cfg']
        kwargs.pop('cfg')

        self._logger = logging.getlogger('access_log')

        super(FileToLogInterface, self).__init__(*args, **kwargs)

    def write(self, msg):
        super(FileToLogInterface, self).write(msg)
        self._logger.info(msg)

其他答案不包括您希望分叉进程共享您的新标准输出的情况。

做那件事:

from os import open, close, dup, O_WRONLY

old = dup(1)
close(1)
open("file", O_WRONLY) # should open on 1

..... do stuff and then restore

close(1)
dup(old) # should dup to 1
close(old) # get rid of left overs

根据这个答案:https://stackoverflow.com/a/5916874/1060344，这是我在我的一个项目中使用的另一种方法。无论你用什么替换sys。Stderr或sys。stderr/ Stdout被用在一些不受你控制的库中，你必须确保替换符合文件接口，特别是当你这样做的时候。该库可能正在使用文件对象的其他方法。

以这种方式检查，我仍然让所有内容都执行stderr/stdout(或任何文件)，并使用Python的日志记录功能将消息发送到日志文件(但你真的可以用它做任何事情):

class FileToLogInterface(file):
    '''
    Interface to make sure that everytime anything is written to stderr, it is
    also forwarded to a file.
    '''

    def __init__(self, *args, **kwargs):
        if 'cfg' not in kwargs:
            raise TypeError('argument cfg is required.')
        else:
            if not isinstance(kwargs['cfg'], config.Config):
                raise TypeError(
                    'argument cfg should be a valid '
                    'PostSegmentation configuration object i.e. '
                    'postsegmentation.config.Config')
        self._cfg = kwargs['cfg']
        kwargs.pop('cfg')

        self._logger = logging.getlogger('access_log')

        super(FileToLogInterface, self).__init__(*args, **kwargs)

    def write(self, msg):
        super(FileToLogInterface, self).write(msg)
        self._logger.info(msg)

以下是Yuda Prawira的回答:

实现flush()和所有文件属性 将其编写为上下文管理器 也捕获stderr

.

import contextlib, sys

@contextlib.contextmanager
def log_print(file):
    # capture all outputs to a log file while still printing it
    class Logger:
        def __init__(self, file):
            self.terminal = sys.stdout
            self.log = file

        def write(self, message):
            self.terminal.write(message)
            self.log.write(message)

        def __getattr__(self, attr):
            return getattr(self.terminal, attr)

    logger = Logger(file)

    _stdout = sys.stdout
    _stderr = sys.stderr
    sys.stdout = logger
    sys.stderr = logger
    try:
        yield logger.log
    finally:
        sys.stdout = _stdout
        sys.stderr = _stderr


with log_print(open('mylogfile.log', 'w')):
    print('hello world')
    print('hello world on stderr', file=sys.stderr)

# you can capture the output to a string with:
# with log_print(io.StringIO()) as log:
#   ....
#   print('[captured output]', log.getvalue())

正如@jfs提到的，大多数解决方案不能正确处理某些类型的stdout输出，例如来自C扩展的输出。在PyPI上有一个名为wurlitzer的模块负责处理所有这些。您只需要它的sys_pipes上下文管理器。简单易用:

from contextlib import redirect_stdout
import os
from wurlitzer import sys_pipes
        
log = open("test.log", "a")
with redirect_stdout(log), sys_pipes():
    print("print statement")
    os.system("echo echo call")

import sys
sys.stdout = open('stdout.txt', 'w')