Cannot Redirect Output When I Run Python Script on Windows Using Just Script's Name

Cannot redirect output when I run Python script on Windows using just script's name

Are you asking about this?

Windows: When executing Python scripts on the command line using file type
associations (i.e. starting "script.py" instead of "python script.py"),
redirects may not work unless you set a specific registry key. See
the Knowledge Base article STDIN/STDOUT Redirection May Not Work If Started from a File Association.

It's in the Python README. Perhaps this patch is what you're looking for.

Redirect stdout to a file in Python?

If you want to do the redirection within the Python script, setting sys.stdout to a file object does the trick:

# for python3
import sys
with open('file', 'w') as sys.stdout:
    print('test')

A far more common method is to use shell redirection when executing (same on Windows and Linux):

$ python3 foo.py > file

how to direct output into a txt file in python in windows

If it were me, I would use David Heffernan's method above to write your variable to the text file (because other methods require the user to use a command prompt).

import itertools  

file = open('out.txt', 'w')
variations = itertools.product('abc', repeat=3)  
for variations in variations:  
    variation_string = ""  
    for letter in variations:  
        variation_string += letter  
    file.write(variation_string)
file.close()

Python Script Called in Powershell Fails to Write to Stdout when Piped to File

The root cause is with the way python handles STDOUT. Python does some low level detection to get the encoding of the system and then uses a io.TextIOWrapper with the encoding set to what it detects and that's what you get in sys.stdout (stderr and stdin have the same).

Now, this detection returns UTF-8 when running in the shell because powershell works in UTF-8 and puts a layer of translation between the system and the running program but when piping to another program the communication is direct without the powershell translation, this direct communication uses the system's encoding which for windows is cp1252 (AKA Windows-1252).

system <(cp1252)> posh <(utf-8)> python # here stdout returns to the shell
system <(cp1252)> posh <(utf-8)> python <(cp1252)> pipe| or redirect> # here stdout moves directly to the next program

As for your issue, without looking at the rest of your program and the input file my best guess is some encoding mismatch, most likely in the reading of the input file, by default python 3+ will read files in utf-8, if this file is in some other encoding you get errors, best case scenario you get garbage text, worst you get an encoding exception.

To solve it you need to know which encoding your input file was created with, which may get tricky and detection is usually slow, other solution would be to work with the files in bytes but this may not be possible depending on the processing done.

How to automatically direct print statements' outputs to a file in python?

I believe this is the closest you'll get:

import sys
sys.stdout = open('file', 'w')
print 'test' # prints test to file

If you'd like to write to multiple locations, you can use the following. Any object with a write method can be assigned to sys.stdout in python.

import sys

class Logger(object):
    def __init__(self, *files):
        self.files = files

    def write(self, obj):
        for f in self.files:
            f.write(obj)

f = open('file', 'w')
sys.stdout = Logger(f, sys.stdout)

print "Python Magic"

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