Python, changing the write method of sys.stdout

Question

I have this code:

class Sstdout(sys):
    def __init__(self,txtctrl):
        self.txtctrl = txtctrl
    def write(self,string):     
        self.txtctrl.write('hi '+string)

sys.stdout.write = Sstdout()    
os.dup2(some_odj.fileno(), sys.stdout.fileno())

Traceback (most recent call last):
    File "for_testing0.py", line 17, in <module>
        os.dup2(sock.fileno(), sys.stdout.fileno())
    AttributeError: 'Sstdout' object has no attribute 'fileno'

The question is how to correctly change only sys.stdout.write method ?

redirection output to a file object. I've changed the question only — vova vova, Jan 27 '15 at 10:22
[Redirect stdout to a file in Python](http://stackoverflow.com/questions/4675728/redirect-stdout-to-a-file-in-python) — Dmitry Nedbaylo, Jan 27 '15 at 10:26
Please post the real code you ran. If you ran the code above, you'd get the error `'file' object attribute 'write' is read-only`. And regarding the error you did get, the error message seems to explain exactly what the problem is. — interjay, Jan 27 '15 at 10:42
I need to chnge what script stdout is before sending the stdout to a file — vova vova, Jan 27 '15 at 10:46

score 0 · Answer 1 · answered Jan 27 '15 at 11:04

For python 3

import sys
import io

class MyStdout(io.TextIOWrapper):

    def __init__(self, msg, *args, **kwargs):
        super().__init__(*args, **kwargs)
        self.msg = msg

    def write(self, data):
        if data != "\n":
            super().write(self.msg)
        super().write(data)


sys.stdout = MyStdout("hi ", buffer=sys.stdout.buffer, line_buffering=True)

print("jim")

# original stdout
sys.__stdout__

Python, changing the write method of sys.stdout

1 Answers1